Regression: https://github.com/go-gitea/gitea/pull/24805
Closes: #25945

- Disallow `javascript`, `vbscript` and `data` (data uri images still
work) url schemes even if all other schemes are allowed
- Fixed older `cbthunderlink` tests

---------

Co-authored-by: delvh <dev.lh@web.de>

- Closes #21146
- Closes #16721

## :warning: BREAKING :warning:
This changes the default behavior to now create links for any URL scheme
when the user uses the markdown form for links (`[label](URL)`), this
doesn't affect the rendering of inline links. To opt-out set the
`markdown.CUSTOM_URL_SCHEMES` setting to a list of allowed schemes, all
other schemes (except `http` and `https`) won't be allowed.

# Before

![image](https://github.com/go-gitea/gitea/assets/20454870/35fa18ce-7dda-4995-b5b3-3f360f38296d)

# After

![image](https://github.com/go-gitea/gitea/assets/20454870/0922216b-0b35-4b77-9919-21a5c21dd5d0)

---------

Signed-off-by: Yarden Shoham <git@yardenshoham.com>
Co-authored-by: Giteabot <teabot@gitea.io>

Change all license headers to comply with REUSE specification.

Fix #16132

Co-authored-by: flynnnnnnnnnn <flynnnnnnnnnn@github>
Co-authored-by: John Olheiser <john.olheiser@gmail.com>

`<span style="color: red">Hello World!</span>` will now be accepted by
Bluemonday, other properties are still disallowed by Bluemonday.

Add nakedret, unconvert, wastedassign, stylecheck and nolintlint linters to improve code readability

- nakedret - https://github.com/alexkohler/nakedret - nakedret is a Go static analysis tool to find naked returns in functions greater than a specified function length.
- unconvert - https://github.com/mdempsky/unconvert - Remove unnecessary type conversions
- wastedassign - https://github.com/sanposhiho/wastedassign -  wastedassign finds wasted assignment statements.
- notlintlint -  Reports ill-formed or insufficient nolint directives
- stylecheck - https://staticcheck.io/docs/checks/#ST - keep style consistent
  - excluded: [ST1003 - Poorly chosen identifier](https://staticcheck.io/docs/checks/#ST1003) and [ST1005 - Incorrectly formatted error string](https://staticcheck.io/docs/checks/#ST1005)

* gofumpt -w -l .

* gofumpt -w -l -extra .

* Add linter

* manual fix

* change make fmt

* Removed unused method.

* No prefix for data uris.

* Added test to prevent regressions.

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Markdown task list improvements

- Remove `.ui` class and wrappers to prevent fomantic from messing with it.
- Change rendered HTML to match GitHub.
- Add custom styling for the checkboxes.

* fix unittest

Co-authored-by: Lauris BH <lauris@nix.lv>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>

* Add test

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Restore checkbox rendering and prevent poor sanitization of spans

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Also fix preview context

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Also fix preview context

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Allow kbd tags

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Add test

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* restructure markup & markdown to prepare for multiple markup languages support

* adjust some functions between markdown and markup

* fix tests

* improve the comments

* Santiation fix from Gogs

* Linting

* Fix build-errors

* still not working

* Fix all the things!

* gofmt

* Add code-injection checks