Refactor docs (#21627)

This patch:
- Rename some files( `.md` to `.en-us.md`), fix missed translation copy
- Update link which shoud be refer to `../hacking-on-gitea/` instead of
`../make/` (outdated)
- Update `_redirects`:
  -  redirect `/{zh-cn|fr-fr}/make/` to `../hacking-on-gitea/`
  - redirect `/zh-cn/third-party-tools/` to `/zh-cn/integrations/`
- Delete duplicated/outdated files.
- Update menu `weight` of developers.zh-cn.md

Signed-off-by: Xinyu Zhou <i@sourcehut.net>

1 files changed, 0 insertions, 280 deletions

diff --git a/docs/content/doc/advanced/mail-templates-us.md b/docs/content/doc/advanced/mail-templates-us.md
deleted file mode 100644
index bd419a617b..0000000000
--- a/docs/content/doc/advanced/mail-templates-us.md
+++ /dev/null
@@ -1,280 +0,0 @@
----
-date: "2019-10-23T17:00:00-03:00"
-title: "Mail templates"
-slug: "mail-templates"
-weight: 45
-toc: false
-draft: false
-menu:
-  sidebar:
-    parent: "advanced"
-    name: "Mail templates"
-    weight: 45
-    identifier: "mail-templates"
----
-
-# Mail templates
-
-**Table of Contents**
-
-{{< toc >}}
-
-To craft the e-mail subject and contents for certain operations, Gitea can be customized by using templates. The templates
-for these functions are located under the [`custom` directory](https://docs.gitea.io/en-us/customizing-gitea/).
-Gitea has an internal template that serves as default in case there's no custom alternative.
-
-Custom templates are loaded when Gitea starts. Changes made to them are not recognized until Gitea is restarted again.
-
-## Mail notifications supporting templates
-
-Currently, the following notification events make use of templates:
-
-| Action name | Usage                                                                                                        |
-| ----------- | ------------------------------------------------------------------------------------------------------------ |
-| `new`       | A new issue or pull request was created.                                                                     |
-| `comment`   | A new comment was created in an existing issue or pull request.                                              |
-| `close`     | An issue or pull request was closed.                                                                         |
-| `reopen`    | An issue or pull request was reopened.                                                                       |
-| `review`    | The head comment of a review in a pull request.                                                              |
-| `approve`   | The head comment of a approving review for a pull request.                                                   |
-| `reject`    | The head comment of a review requesting changes for a pull request.                                          |
-| `code`      | A single comment on the code of a pull request.                                                              |
-| `assigned`  | Used was assigned to an issue or pull request.                                                               |
-| `default`   | Any action not included in the above categories, or when the corresponding category template is not present. |
-
-The path for the template of a particular message type is:
-
-```sh
-custom/templates/mail/{action type}/{action name}.tmpl
-```
-
-Where `{action type}` is one of `issue` or `pull` (for pull requests), and `{action name}` is one of the names listed above.
-
-For example, the specific template for a mail regarding a comment in a pull request is:
-
-```sh
-custom/templates/mail/pull/comment.tmpl
-```
-
-However, creating templates for each and every action type/name combination is not required.
-A fallback system is used to choose the appropriate template for an event. The _first existing_
-template on this list is used:
-
-- The specific template for the desired **action type** and **action name**.
-- The template for action type `issue` and the desired **action name**.
-- The template for the desired **action type**, action name `default`.
-- The template for action type `issue`, action name `default`.
-
-The only mandatory template is action type `issue`, action name `default`, which is already embedded in Gitea
-unless it's overridden by the user in the `custom` directory.
-
-## Template syntax
-
-Mail templates are UTF-8 encoded text files that need to follow one of the following formats:
-
-```
-Text and macros for the subject line
-------------
-Text and macros for the mail body
-```
-
-or
-
-```
-Text and macros for the mail body
-```
-
-Specifying a _subject_ section is optional (and therefore also the dash line separator). When used, the separator between
-_subject_ and _mail body_ templates requires at least three dashes; no other characters are allowed in the separator line.
-
-_Subject_ and _mail body_ are parsed by [Golang's template engine](https://golang.org/pkg/text/template/) and
-are provided with a _metadata context_ assembled for each notification. The context contains the following elements:
-
-| Name               | Type             | Available     | Usage                                                                                                                                                                                                                                             |
-| ------------------ | ---------------- | ------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-| `.FallbackSubject` | string           | Always        | A default subject line. See Below.                                                                                                                                                                                                                |
-| `.Subject`         | string           | Only in body  | The _subject_, once resolved.                                                                                                                                                                                                                     |
-| `.Body`            | string           | Always        | The message of the issue, pull request or comment, parsed from Markdown into HTML and sanitized. Do not confuse with the _mail body_.                                                                                                             |
-| `.Link`            | string           | Always        | The address of the originating issue, pull request or comment.                                                                                                                                                                                    |
-| `.Issue`           | models.Issue     | Always        | The issue (or pull request) originating the notification. To get data specific to a pull request (e.g. `HasMerged`), `.Issue.PullRequest` can be used, but care should be taken as this field will be `nil` if the issue is _not_ a pull request. |
-| `.Comment`         | models.Comment   | If applicable | If the notification is from a comment added to an issue or pull request, this will contain the information about the comment.                                                                                                                     |
-| `.IsPull`          | bool             | Always        | `true` if the mail notification is associated with a pull request (i.e. `.Issue.PullRequest` is not `nil`).                                                                                                                                       |
-| `.Repo`            | string           | Always        | Name of the repository, including owner name (e.g. `mike/stuff`)                                                                                                                                                                                  |
-| `.User`            | models.User      | Always        | Owner of the repository from which the event originated. To get the user name (e.g. `mike`),`.User.Name` can be used.                                                                                                                             |
-| `.Doer`            | models.User      | Always        | User that executed the action triggering the notification event. To get the user name (e.g. `rhonda`), `.Doer.Name` can be used.                                                                                                                  |
-| `.IsMention`       | bool             | Always        | `true` if this notification was only generated because the user was mentioned in the comment, while not being subscribed to the source. It will be `false` if the recipient was subscribed to the issue or repository.                            |
-| `.SubjectPrefix`   | string           | Always        | `Re: ` if the notification is about other than issue or pull request creation; otherwise an empty string.                                                                                                                                         |
-| `.ActionType`      | string           | Always        | `"issue"` or `"pull"`. Will correspond to the actual _action type_ independently of which template was selected.                                                                                                                                  |
-| `.ActionName`      | string           | Always        | It will be one of the action types described above (`new`, `comment`, etc.), and will correspond to the actual _action name_ independently of which template was selected.                                                                        |
-| `.ReviewComments`  | []models.Comment | Always        | List of code comments in a review. The comment text will be in `.RenderedContent` and the referenced code will be in `.Patch`.                                                                                                                    |
-
-All names are case sensitive.
-
-### The _subject_ part of the template
-
-The template engine used for the mail _subject_ is golang's [`text/template`](https://golang.org/pkg/text/template/).
-Please refer to the linked documentation for details about its syntax.
-
-The _subject_ is built using the following steps:
-
-- A template is selected according to the type of notification and to what templates are present.
-- The template is parsed and resolved (e.g. `{{.Issue.Index}}` is converted to the number of the issue
-  or pull request).
-- All space-like characters (e.g. `TAB`, `LF`, etc.) are converted to normal spaces.
-- All leading, trailing and redundant spaces are removed.
-- The string is truncated to its first 256 runes (characters).
-
-If the end result is an empty string, **or** no subject template was available (i.e. the selected template
-did not include a subject part), Gitea's **internal default** will be used.
-
-The internal default (fallback) subject is the equivalent of:
-
-```sh
-{{.SubjectPrefix}}[{{.Repo}}] {{.Issue.Title}} (#{{.Issue.Index}})
-```
-
-For example: `Re: [mike/stuff] New color palette (#38)`
-
-Gitea's default subject can also be found in the template _metadata_ as `.FallbackSubject` from any of
-the two templates, even if a valid subject template is present.
-
-### The _mail body_ part of the template
-
-The template engine used for the _mail body_ is golang's [`html/template`](https://golang.org/pkg/html/template/).
-Please refer to the linked documentation for details about its syntax.
-
-The _mail body_ is parsed after the mail subject, so there is an additional _metadata_ field which is
-the actual rendered subject, after all considerations.
-
-The expected result is HTML (including structural elements like`<html>`, `<body>`, etc.). Styling
-through `<style>` blocks, `class` and `style` attributes is possible. However, `html/template`
-does some [automatic escaping](https://golang.org/pkg/html/template/#hdr-Contexts) that should be considered.
-
-Attachments (such as images or external style sheets) are not supported. However, other templates can
-be referenced too, for example to provide the contents of a `<style>` element in a centralized fashion.
-The external template must be placed under `custom/mail` and referenced relative to that directory.
-For example, `custom/mail/styles/base.tmpl` can be included using `{{template styles/base}}`.
-
-The mail is sent with `Content-Type: multipart/alternative`, so the body is sent in both HTML
-and text formats. The latter is obtained by stripping the HTML markup.
-
-## Troubleshooting
-
-How a mail is rendered is directly dependent on the capabilities of the mail application. Many mail
-clients don't even support HTML, so they show the text version included in the generated mail.
-
-If the template fails to render, it will be noticed only at the moment the mail is sent.
-A default subject is used if the subject template fails, and whatever was rendered successfully
-from the the _mail body_ is used, disregarding the rest.
-
-Please check [Gitea's logs](https://docs.gitea.io/en-us/logging-configuration/) for error messages in case of trouble.
-
-## Example
-
-`custom/templates/mail/issue/default.tmpl`:
-
-```html
-[{{.Repo}}] @{{.Doer.Name}}
-{{if eq .ActionName "new"}}
-    created
-{{else if eq .ActionName "comment"}}
-    commented on
-{{else if eq .ActionName "close"}}
-    closed
-{{else if eq .ActionName "reopen"}}
-    reopened
-{{else}}
-    updated
-{{end}}
-{{if eq .ActionType "issue"}}
-    issue
-{{else}}
-    pull request
-{{end}}
-#{{.Issue.Index}}: {{.Issue.Title}}
-------------
-<!DOCTYPE html>
-<html>
-<head>
-    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
-    <title>{{.Subject}}</title>
-</head>
-
-<body>
-    {{if .IsMention}}
-    <p>
-        You are receiving this because @{{.Doer.Name}} mentioned you.
-    </p>
-    {{end}}
-    <p>
-        <p>
-        <a href="{{AppUrl}}/{{.Doer.LowerName}}">@{{.Doer.Name}}</a>
-        {{if not (eq .Doer.FullName "")}}
-            ({{.Doer.FullName}})
-        {{end}}
-        {{if eq .ActionName "new"}}
-            created
-        {{else if eq .ActionName "close"}}
-            closed
-        {{else if eq .ActionName "reopen"}}
-            reopened
-        {{else}}
-            updated
-        {{end}}
-        <a href="{{.Link}}">{{.Repo}}#{{.Issue.Index}}</a>.
-        </p>
-        {{if not (eq .Body "")}}
-            <h3>Message content:</h3>
-            <hr>
-            {{.Body | Str2html}}
-        {{end}}
-    </p>
-    <hr>
-    <p>
-        <a href="{{.Link}}">View it on Gitea</a>.
-    </p>
-</body>
-</html>
-```
-
-This template produces something along these lines:
-
-### Subject
-
-> [mike/stuff] @rhonda commented on pull request #38: New color palette
-
-### Mail body
-
-> [@rhonda](#) (Rhonda Myers) updated [mike/stuff#38](#).
->
-> #### Message content:
->
-> \_********************************\_********************************
->
-> Mike, I think we should tone down the blues a little.
-> \_********************************\_********************************
->
-> [View it on Gitea](#).
-
-## Advanced
-
-The template system contains several functions that can be used to further process and format
-the messages. Here's a list of some of them:
-
-| Name             | Parameters  | Available | Usage                                                                       |
-| ---------------- | ----------- | --------- | --------------------------------------------------------------------------- |
-| `AppUrl`         | -           | Any       | Gitea's URL                                                                 |
-| `AppName`        | -           | Any       | Set from `app.ini`, usually "Gitea"                                         |
-| `AppDomain`      | -           | Any       | Gitea's host name                                                           |
-| `EllipsisString` | string, int | Any       | Truncates a string to the specified length; adds ellipsis as needed         |
-| `Str2html`       | string      | Body only | Sanitizes text by removing any HTML tags from it.                           |
-| `Safe`           | string      | Body only | Takes the input as HTML; can be used for `.ReviewComments.RenderedContent`. |
-
-These are _functions_, not metadata, so they have to be used:
-
-```html
-Like this:         {{Str2html "Escape<my>text"}}
-Or this:           {{"Escape<my>text" | Str2html}}
-Or this:           {{AppUrl}}
-But not like this: {{.AppUrl}}
-```