Docs: Enable gitlab-docs lint

Closes gitlab-com/gitlab-docs#305

See merge request gitlab-org/gitlab-ce!23748

[CE] Fix DiffCheck failing due to invalid string argument

See merge request gitlab-org/gitlab-ce!23741

Docs: Fix links to sections that were moved

See merge request gitlab-org/gitlab-ce!23750

Add spec for plain diff/email patch

Closes #52696

See merge request gitlab-org/gitlab-ce!23529

Check that yarn version is at least 1.10.0

See merge request gitlab-org/gitlab-ce!23612

Fix a potential frozen string error in app/mailers/notify.rb

Closes #55183

See merge request gitlab-org/gitlab-ce!23728

Migrate timeline_entry_item_spec.js to Jest

See merge request gitlab-org/gitlab-ce!23686

Apply existing dropdown item styles to .dropdown-item class

See merge request gitlab-org/gitlab-ce!23663

Docs: update Web IDE docs

See merge request gitlab-org/gitlab-ce!23735

Add spec file using before(:context) to reduce test time. With testing
almost identical things, unnecessary to make them completely atomic.
Includes two helper methods. Since the raw_content method is the only
function needed on that page, created the method in the spec instead
of adding another page object.

Setup new project/commit page object and update project/show to add
go_to_commit method. The go_to_commit method is near duplicate of
go_to_file method, but decided to split them off to reduce overall
refactoring and simplify language.

Also add selectors to commit box partial and update qa.rb to load
new page object.

Update GitLab Workhorse to v8.0.0

Closes #55191

See merge request gitlab-org/gitlab-ce!23740

Hot patch for #55137

Generalise test compare service

See merge request gitlab-org/gitlab-ce!22833

Add note about allow_failure default value for manual jobs

See merge request gitlab-org/gitlab-ce!23685

Added docs for similar issues

Closes #55194

See merge request gitlab-org/gitlab-ce!23403

Patch 35

See merge request gitlab-org/gitlab-ce!23711

Add documentation note about not nesting storage paths

See merge request gitlab-org/gitlab-ce!23722

Remove boxes around code comments

Closes #54030 and #54058

See merge request gitlab-org/gitlab-ce!23092

Signed-off-by: Rémy Coutable <remy@rymai.me>

Add missing links to resources

See merge request gitlab-org/gitlab-ce!23605

Docs: how the global nav works

Closes gitlab-com/gitlab-docs#260

See merge request gitlab-org/gitlab-ce!23065

Remove deprecated `vlink` class

See merge request gitlab-org/gitlab-ce!23588

Migrate emoji_menu_spec.js to Jest

See merge request gitlab-org/gitlab-ce!23688