Add markdownlint (#20512)

Add `markdownlint` linter and fix issues. Config is based on the one
from electron's repo with a few rules relaxed.

3 files changed, 84 insertions, 48 deletions

diff --git a/docs/content/doc/help/faq.en-us.md b/docs/content/doc/help/faq.en-us.md
index 5783169fa9..17983da695 100644
--- a/docs/content/doc/help/faq.en-us.md
+++ b/docs/content/doc/help/faq.en-us.md
@@ -15,7 +15,8 @@ menu:
 
 # Frequently Asked Questions <!-- omit in toc -->
 
-This page contains some common questions and answers.  
+This page contains some common questions and answers.
+
 For more help resources, check all [Support Options]({{< relref "doc/help/seek-help.en-us.md" >}}).
 
 **Table of Contents**
@@ -24,14 +25,18 @@ For more help resources, check all [Support Options]({{< relref "doc/help/seek-h
 
 ## Difference between 1.x and 1.x.x downloads
 
-Version 1.7.x will be used for this example.  
+Version 1.7.x will be used for this example.
+
 **NOTE:** this example applies to Docker images as well!
 
-On our [downloads page](https://dl.gitea.io/gitea/) you will see a 1.7 directory, as well as directories for 1.7.0, 1.7.1, 1.7.2, 1.7.3, 1.7.4, 1.7.5, and 1.7.6.  
-The 1.7 and 1.7.0 directories are **not** the same. The 1.7 directory is built on each merged commit to the [`release/v1.7`](https://github.com/go-gitea/gitea/tree/release/v1.7) branch.  
+On our [downloads page](https://dl.gitea.io/gitea/) you will see a 1.7 directory, as well as directories for 1.7.0, 1.7.1, 1.7.2, 1.7.3, 1.7.4, 1.7.5, and 1.7.6.
+
+The 1.7 and 1.7.0 directories are **not** the same. The 1.7 directory is built on each merged commit to the [`release/v1.7`](https://github.com/go-gitea/gitea/tree/release/v1.7) branch.
+
 The 1.7.0 directory, however, is a build that was created when the [`v1.7.0`](https://github.com/go-gitea/gitea/releases/tag/v1.7.0) tag was created.
 
-This means that 1.x downloads will change as commits are merged to their respective branch (think of it as a separate "main" branch for each release).  
+This means that 1.x downloads will change as commits are merged to their respective branch (think of it as a separate "main" branch for each release).
+
 On the other hand, 1.x.x downloads should never change.
 
 ## How to migrate from Gogs/GitHub/etc. to Gitea
@@ -41,11 +46,14 @@ To migrate from Gogs to Gitea:
 - [Gogs version 0.9.146 or less]({{< relref "doc/upgrade/from-gogs.en-us.md" >}})
 - [Gogs version 0.11.46.0418](https://github.com/go-gitea/gitea/issues/4286)
 
-To migrate from GitHub to Gitea, you can use Gitea's built-in migration form.  
-In order to migrate items such as issues, pull requests, etc. you will need to input at least your username.  
+To migrate from GitHub to Gitea, you can use Gitea's built-in migration form.
+
+In order to migrate items such as issues, pull requests, etc. you will need to input at least your username.
+
 [Example (requires login)](https://try.gitea.io/repo/migrate)
 
-To migrate from GitLab to Gitea, you can use this non-affiliated tool:  
+To migrate from GitLab to Gitea, you can use this non-affiliated tool:
+
 https://github.com/loganinak/MigrateGitlabToGogs
 
 ## Where does Gitea store what file
@@ -83,9 +91,9 @@ There are a few places that could make this show incorrectly.
 
 If certain clone options aren't showing up (HTTP/S or SSH), the following options can be checked in your `app.ini`
 
-`DISABLE_HTTP_GIT`: if set to true, there will be no HTTP/HTTPS link  
-`DISABLE_SSH`: if set to true, there will be no SSH link  
-`SSH_EXPOSE_ANONYMOUS`: if set to false, SSH links will be hidden for anonymous users
+- `DISABLE_HTTP_GIT`: if set to true, there will be no HTTP/HTTPS link
+- `DISABLE_SSH`: if set to true, there will be no SSH link
+- `SSH_EXPOSE_ANONYMOUS`: if set to false, SSH links will be hidden for anonymous users
 
 ## File upload fails with: 413 Request Entity Too Large
 
@@ -95,19 +103,21 @@ See the [reverse proxy guide]({{< relref "doc/usage/reverse-proxies.en-us.md" >}
 
 ## Custom Templates not loading or working incorrectly
 
-Gitea's custom templates must be added to the correct location or Gitea will not find and use them.  
+Gitea's custom templates must be added to the correct location or Gitea will not find and use them.
+
 The correct path for the template(s) will be relative to the `CustomPath`
 
 1. To find `CustomPath`, look for Custom File Root Path in Site Administration -> Configuration
 
-- If that doesn't exist, you can try `echo $GITEA_CUSTOM`
+    If that doesn't exist, you can try `echo $GITEA_CUSTOM`
 
-2. If you are still unable to find a path, the default can be [calculated above](#where-does-gitea-store-x-file)
+2. If you are still unable to find a path, the default can be [calculated above](#where-does-gitea-store-what-file)
 3. Once you have figured out the correct custom path, you can refer to the [customizing Gitea]({{< relref "doc/advanced/customizing-gitea.en-us.md" >}}) page to add your template to the correct location.
 
 ## Active user vs login prohibited user
 
-In Gitea, an "active" user refers to a user that has activated their account via email.  
+In Gitea, an "active" user refers to a user that has activated their account via email.
+
 A "login prohibited" user is a user that is not allowed to log in to Gitea anymore
 
 ## Setting up logging
@@ -116,8 +126,10 @@ A "login prohibited" user is a user that is not allowed to log in to Gitea anymo
 
 ## What is Swagger?
 
-[Swagger](https://swagger.io/) is what Gitea uses for its API.  
-All Gitea instances have the built-in API, though it can be disabled by setting `ENABLE_SWAGGER` to `false` in the `api` section of your `app.ini`  
+[Swagger](https://swagger.io/) is what Gitea uses for its API.
+
+All Gitea instances have the built-in API, though it can be disabled by setting `ENABLE_SWAGGER` to `false` in the `api` section of your `app.ini`
+
 For more information, refer to Gitea's [API docs]({{< relref "doc/developers/api-usage.en-us.md" >}})
 
 [Swagger Example](https://try.gitea.io/api/swagger)
@@ -139,7 +151,8 @@ You can configure `EMAIL_DOMAIN_WHITELIST` or `EMAIL_DOMAIN_BLOCKLIST` in your a
 
 ### Only allow/block certain OpenID providers
 
-You can configure `WHITELISTED_URIS` or `BLACKLISTED_URIS` under `[openid]` in your `app.ini`  
+You can configure `WHITELISTED_URIS` or `BLACKLISTED_URIS` under `[openid]` in your `app.ini`
+
 **NOTE:** whitelisted takes precedence, so if it is non-blank then blacklisted is ignored
 
 ### Issue only users
@@ -163,38 +176,48 @@ Use [Fail2Ban]({{< relref "doc/usage/fail2ban-setup.en-us.md" >}}) to monitor an
 Gitea supports three official themes right now, `gitea` (light), `arc-green` (dark), and `auto` (automatically switches between the previous two depending on operating system settings).
 To add your own theme, currently the only way is to provide a complete theme (not just color overrides)
 
-As an example, let's say our theme is `arc-blue` (this is a real theme, and can be found [in this issue](https://github.com/go-gitea/gitea/issues/6011))  
-Name the `.css` file `theme-arc-blue.css` and add it to your custom folder in `custom/public/css`  
+As an example, let's say our theme is `arc-blue` (this is a real theme, and can be found [in this issue](https://github.com/go-gitea/gitea/issues/6011))
+
+Name the `.css` file `theme-arc-blue.css` and add it to your custom folder in `custom/public/css`
+
 Allow users to use it by adding `arc-blue` to the list of `THEMES` in your `app.ini`
 
 ## SSHD vs built-in SSH
 
-SSHD is the built-in SSH server on most Unix systems.  
+SSHD is the built-in SSH server on most Unix systems.
+
 Gitea also provides its own SSH server, for usage when SSHD is not available.
 
 ## Gitea is running slow
 
-The most common culprit for this is loading federated avatars.  
-This can be turned off by setting `ENABLE_FEDERATED_AVATAR` to `false` in your `app.ini`  
+The most common culprit for this is loading federated avatars.
+
+This can be turned off by setting `ENABLE_FEDERATED_AVATAR` to `false` in your `app.ini`
+
 Another option that may need to be changed is setting `DISABLE_GRAVATAR` to `true` in your `app.ini`
 
 ## Can't create repositories/files
 
-Make sure that Gitea has sufficient permissions to write to its home directory and data directory.  
-See [AppDataPath and RepoRootPath](#where-does-gitea-store-x-file)
+Make sure that Gitea has sufficient permissions to write to its home directory and data directory.
+
+See [AppDataPath and RepoRootPath](#where-does-gitea-store-what-file)
 
 **Note for Arch users:** At the time of writing this, there is an issue with the Arch package's systemd file including this line:
-`ReadWritePaths=/etc/gitea/app.ini`  
+
+`ReadWritePaths=/etc/gitea/app.ini`
+
 Which makes all other paths non-writeable to Gitea.
 
 ## Translation is incorrect/how to add more translations
 
-Our translations are currently crowd-sourced on our [Crowdin project](https://crowdin.com/project/gitea)  
+Our translations are currently crowd-sourced on our [Crowdin project](https://crowdin.com/project/gitea)
+
 Whether you want to change a translation or add a new one, it will need to be there as all translations are overwritten in our CI via the Crowdin integration.
 
 ## Hooks aren't running
 
-If Gitea is not running hooks, a common cause is incorrect setup of SSH keys.  
+If Gitea is not running hooks, a common cause is incorrect setup of SSH keys.
+
 See [SSH Issues](#ssh-issues) for more information.
 
 You can also try logging into the administration panel and running the `Resynchronize pre-receive, update and post-receive hooks of all repositories.` option.
@@ -203,7 +226,8 @@ You can also try logging into the administration panel and running the `Resynchr
 
 If you cannot reach repositories over `ssh`, but `https` works fine, consider looking into the following.
 
-First, make sure you can access Gitea via SSH.  
+First, make sure you can access Gitea via SSH.
+
 `ssh git@myremote.example`
 
 If the connection is successful, you should receive an error message like the following:
@@ -236,7 +260,8 @@ following things:
 - On the server:
   - Make sure the repository exists and is correctly named.
   - Check the permissions of the `.ssh` directory in the system user's home directory.
-  - Verify that the correct public keys are added to `.ssh/authorized_keys`.  
+  - Verify that the correct public keys are added to `.ssh/authorized_keys`.
+
     Try to run `Rewrite '.ssh/authorized_keys' file (for Gitea SSH keys)` on the
     Gitea admin panel.
   - Read Gitea logs.
@@ -289,7 +314,8 @@ Check that you have proper access to the repository
 error: failed to push some refs to '<GIT_REPO_URL>'
 ```
 
-Check the value of `LFS_HTTP_AUTH_EXPIRY` in your `app.ini` file.  
+Check the value of `LFS_HTTP_AUTH_EXPIRY` in your `app.ini` file.
+
 By default, your LFS token will expire after 20 minutes. If you have a slow connection or a large file (or both), it may not finish uploading within the time limit.
 
 You may want to set this value to `60m` or `120m`.
@@ -306,17 +332,21 @@ There is no setting for password resets. It is enabled when a [mail service]({{<
 
 - As an **admin**, you can change any user's password (and optionally force them to change it on next login)...
   - By navigating to your `Site Administration -> User Accounts` page and editing a user.
-  - By using the [admin CLI commands]({{< relref "doc/usage/command-line.en-us.md#admin" >}}).  
+  - By using the [admin CLI commands]({{< relref "doc/usage/command-line.en-us.md#admin" >}}).
+
     Keep in mind most commands will also need a [global flag]({{< relref "doc/usage/command-line.en-us.md#global-options" >}}) to point the CLI at the correct configuration.
 - As a **user** you can change it...
   - In your account `Settings -> Account` page (this method **requires** you to know your current password).
-  - By using the `Forgot Password` link.  
+  - By using the `Forgot Password` link.
+
     If the `Forgot Password/Account Recovery` page is disabled, please contact your administrator to configure a [mail service]({{< relref "doc/usage/email-setup.en-us.md" >}}).
 
 ## Why is my markdown broken
 
-In Gitea version `1.11` we moved to [goldmark](https://github.com/yuin/goldmark) for markdown rendering, which is [CommonMark](https://commonmark.org/) compliant.  
-If you have markdown that worked as you expected prior to version `1.11` and after upgrading it's not working anymore, please look through the CommonMark spec to see whether the problem is due to a bug or non-compliant syntax.  
+In Gitea version `1.11` we moved to [goldmark](https://github.com/yuin/goldmark) for markdown rendering, which is [CommonMark](https://commonmark.org/) compliant.
+
+If you have markdown that worked as you expected prior to version `1.11` and after upgrading it's not working anymore, please look through the CommonMark spec to see whether the problem is due to a bug or non-compliant syntax.
+
 If it is the latter, _usually_ there is a compliant alternative listed in the spec.
 
 ## Upgrade errors with MySQL
@@ -332,8 +362,10 @@ is too small. Gitea requires that the `ROWFORMAT` for its tables is `DYNAMIC`.
 
 If you are receiving an error line containing `Error 1071: Specified key was too long; max key length is 1000 bytes...`
 then you are attempting to run Gitea on tables which use the ISAM engine. While this may have worked by chance in previous versions of Gitea, it has never been officially supported and
-you must use InnoDB. You should run `ALTER TABLE table_name ENGINE=InnoDB;` for each table in the database.  
+you must use InnoDB. You should run `ALTER TABLE table_name ENGINE=InnoDB;` for each table in the database.
+
 If you are using MySQL 5, another possible fix is
+
 ```mysql
 SET GLOBAL innodb_file_format=Barracuda;
 SET GLOBAL innodb_file_per_table=1;
@@ -404,8 +436,8 @@ gitea doctor recreate-table
 
 It is highly recommended to back-up your database before running these commands.
 
-
 ## Why are tabs/indents wrong when viewing files
 
-If you are using Cloudflare, turn off the auto-minify option in the dashboard.  
+If you are using Cloudflare, turn off the auto-minify option in the dashboard.
+
 `Speed` -> `Optimization` -> Uncheck `HTML` within the `Auto-Minify` settings.
diff --git a/docs/content/doc/help/seek-help.en-us.md b/docs/content/doc/help/seek-help.en-us.md
index f1a93eacea..fe898e34b9 100644
--- a/docs/content/doc/help/seek-help.en-us.md
+++ b/docs/content/doc/help/seek-help.en-us.md
@@ -22,9 +22,10 @@ menu:
 
 1. Your `app.ini` (with any sensitive data scrubbed as necessary).
 2. The Gitea logs, and any other appropriate log files for the situation.
-    * The logs are likely to be outputted to console. If you need to collect logs from files, 
+    - The logs are likely to be outputted to console. If you need to collect logs from files,
       you could copy the following config into your `app.ini` (remove all other `[log]` sections),
       then you can find the `*.log` files in Gitea's log directory (default: `%(GITEA_WORK_DIR)/log`).
+
     ```ini
     ; To show all SQL logs, you can also set LOG_SQL=true in the [database] section 
     [log]
@@ -38,17 +39,20 @@ menu:
     FILE_NAME=router.log
     [log.file.xorm]
     FILE_NAME=xorm.log
-    ``` 
+    ```
+
 3. Any error messages you are seeing.
 4. When possible, try to replicate the issue on [try.gitea.io](https://try.gitea.io) and include steps so that others can reproduce the issue.
-    * This will greatly improve the chance that the root of the issue can be quickly discovered and resolved.
+    - This will greatly improve the chance that the root of the issue can be quickly discovered and resolved.
 5. If you meet slow/hanging/deadlock problems, please report the stack trace when the problem occurs:
     1. Enable pprof in `app.ini` and restart Gitea
-    ```ini
-    [server]
-    ENABLE_PPROF = true
-    ```
-    2. Trigger the bug, when Gitea gets stuck, use curl or browser to visit: `http://127.0.0.1:6060/debug/pprof/goroutine?debug=1` (IP must be `127.0.0.1` and port must be `6060`). 
+
+        ```ini
+        [server]
+        ENABLE_PPROF = true
+        ```
+
+    2. Trigger the bug, when Gitea gets stuck, use curl or browser to visit: `http://127.0.0.1:6060/debug/pprof/goroutine?debug=1` (IP must be `127.0.0.1` and port must be `6060`).
     3. If you are using Docker, please use `docker exec -it <container-name> curl "http://127.0.0.1:6060/debug/pprof/goroutine?debug=1"`.
     4. Report the output (the stack trace doesn't contain sensitive data)
 
diff --git a/docs/content/doc/help/seek-help.zh-tw.md b/docs/content/doc/help/seek-help.zh-tw.md
index 3d45e6c3b2..f9107a026b 100644
--- a/docs/content/doc/help/seek-help.zh-tw.md
+++ b/docs/content/doc/help/seek-help.zh-tw.md
@@ -22,10 +22,10 @@ menu:
 
 1. 您的 `app.ini` (必要時清除掉任何機密資訊)
 2. `gitea.log` (以及任何有關的日誌檔案)
-    * 例：如果錯誤和資料庫相關，提供 `xorm.log` 可能會有幫助
+    - 例：如果錯誤和資料庫相關，提供 `xorm.log` 可能會有幫助
 3. 您看到的任何錯誤訊息
 4. 儘可能地在 [try.gitea.io](https://try.gitea.io) 觸發您的問題並記下步驟，以便其他人能重現那個問題。
-    * 這將讓我們更有機會快速地找出問題的根源並解決它。
+    - 這將讓我們更有機會快速地找出問題的根源並解決它。
 5. 堆棧跟踪，[請參考英文文檔](https://docs.gitea.io/en-us/seek-help/)
 
 ## 錯誤回報