docs/Tsumitsu Fix render issue in GFM documentation page

See merge request gitlab-org/gitlab-ce!21997

Use the standard PIP_CACHE_DIR for Python dependency caching template

Closes #52408

See merge request gitlab-org/gitlab-ce!22211

Fix links that 404 and style changes

See merge request gitlab-org/gitlab-ce!22209

Reject invalid branch names in repository compare controller

Closes #51003

See merge request gitlab-org/gitlab-ce!22186

Rails5: fix user edit profile clear status spec

See merge request gitlab-org/gitlab-ce!22169

Update to latest version of contributor-covenant.

See merge request gitlab-org/gitlab-ce!21995

QA: Allow the registration e2e test to be skipped

See merge request gitlab-org/gitlab-ce!22205

Signed-off-by: Takuya Noguchi <takninnovationresearch@gmail.com>

- Some links internal links were incorrect.
- Removed some #overview anchor links, because they don't
  jump much content.
- Made text confirm to suggested proselint and mardownlint rules.

Bump rugged to 0.27.5 for security fixes

See merge request gitlab-org/gitlab-ce!22208

See: https://github.com/libgit2/libgit2/releases

Closes #51003

Merge branch '52353-keyboard-navigation-project-slug-is-not-focused-on-new-project-page' into 'master'

Resolve "Keyboard navigation: "Project slug" is not focused on "New project" page"

Closes #52353

See merge request gitlab-org/gitlab-ce!22198

If SIGNUP_DISABLED is true skip any tests with a context
:skip_signup_disabled. The context is set for the registration tests.
This allows the tests to be skipped when run on the staging, which
doesn't allow registration

Removes expensive dead code on main MR page request

Closes #51172

See merge request gitlab-org/gitlab-ce!22153

Remove duplicate button from the markdown header toolbar

See merge request gitlab-org/gitlab-ce!22192

Resolve "Pipeline graph is not vertically aligned in commit page"

Closes #52193

See merge request gitlab-org/gitlab-ce!22173

Fix comments in app/models/note.rb

See merge request gitlab-org/gitlab-ce!22171

Update installation and update docs for 11 4

See merge request gitlab-org/gitlab-ce!22030

Clean up ActiveRecord code in TodosFinder and TodoService

See merge request gitlab-org/gitlab-ce!21838

Add note in docs for docker executor for interactive web terminal

See merge request gitlab-org/gitlab-ce!21880

Fix links to auth resources external to docs

See merge request gitlab-org/gitlab-ce!22180

This refactors the TodoService class according to our code reuse
guidelines. The resulting code is a wee bit more verbose, but it allows
us to decouple the column names from the input, resulting in fewer
changes being necessary when we change the schema.

One particular noteworthy line in TodoService is the following:

    todos_ids = todos.update_state(state)

Technically this is a violation of the guidelines, because
`update_state` is a class method, which services are not supposed to use
(safe for a few allowed ones). I decided to keep this, since there is no
alternative. `update_state` doesn't produce a relation so it doesn't
belong in a Finder, and we can't move it to another Service either. As
such I opted to just use the method directly.

Cases like this may happen more frequently, at which point we should
update our documentation with some sort of recommendation. For now, I
want to refrain from doing so until we have a few more examples.

This refactors the TodosFinder finder according to the new code reuse
rules, as enforced by the CodeReuse cops. I also changed some of the
methods to use regular if statements, instead of assignments and/or
early returns. This results in a more natural flow when reading the
code, and it makes it harder to accidentally return the wrong result.

docs: cleanup term settings wording

See merge request gitlab-org/gitlab-ce!22162

Replace old "secret variables" image for variables with new "variables" image

See merge request gitlab-org/gitlab-ce!22184

Redirect to the pipeline builds page when a build is canceled

Closes #39161

See merge request gitlab-org/gitlab-ce!21595

Resolve "Merge request buttons spacing incorrect"

Closes #48494

See merge request gitlab-org/gitlab-ce!22135

Docs - Prefilled fields for new issue link

See merge request gitlab-org/gitlab-ce!22082

Added note to clarify values for hook-name.d

See merge request gitlab-org/gitlab-ce!22165

Improve QA page README

See merge request gitlab-org/gitlab-ce!22176