Docs: Fixing anchors and links for all docs related to issues.

See merge request gitlab-org/gitlab-ce!25516

Add instance level templates to the examples page.

See merge request gitlab-org/gitlab-ce!25927

Fix link to personas UX guide

See merge request gitlab-org/gitlab-ce!26478

Move details of e2e tests to the bottom

See merge request gitlab-org/gitlab-ce!26494

Set proper default-branch on GitHub Import

Closes #59347

See merge request gitlab-org/gitlab-ce!26476

Refresh commit count after repository head changes

Closes #59346

See merge request gitlab-org/gitlab-ce!26473

Resolve ""Create project label" window is cut off at the bottom"

Closes #46787

See merge request gitlab-org/gitlab-ce!26049

The code should be written like a newspaper, wherein the top we
have more high level information, and as we go down we have more
details.

So I'm moving the implementation details to the bottom to make the
test easier to read.

Freeze strings in email service specs

See merge request gitlab-org/gitlab-ce!26485

Extract EE specific files/lines for Release app/serializers

See merge request gitlab-org/gitlab-ce!26087

Bump pg gem from 1.1.3 to 1.1.4

See merge request gitlab-org/gitlab-ce!26471

Revert "Merge branch 'winh-remove-sushi' into 'master'"

See merge request gitlab-org/gitlab-ce!26470

This keeps the version used by gitlab-monitor and GitLab CE
consistent. This release also adds Ruby 2.6 support and PostgreSQL 11
error codes:

https://github.com/ged/ruby-pg/blob/master/History.rdoc

[CE] Extract EE specific files/lines from spec/finders

Closes gitlab-ee#10142 and gitlab-ee#10141

See merge request gitlab-org/gitlab-ce!26337

This reverts merge request !26430

Add end-of-string to regex example

Closes #58031

See merge request gitlab-org/gitlab-ce!26302

Docs cleanup fe

See merge request gitlab-org/gitlab-ce!26158

Add highest_role method to User

See merge request gitlab-org/gitlab-ce!25462

Implemented trimming for item's name in Web IDE

Closes #57540

See merge request gitlab-org/gitlab-ce!26270

Mock and wait for timers in Jest

Closes #56056

See merge request gitlab-org/gitlab-ce!26433

Automate base domain help text on Clusters page

Closes #57357

See merge request gitlab-org/gitlab-ce!26124

Display draft when toggling replies

Closes #48211 and #56364

See merge request gitlab-org/gitlab-ce!25563

Display the database adapter name in a human-friendly way

See merge request gitlab-org/gitlab-ce!26437

Improve Youtrack documentation for style

See merge request gitlab-org/gitlab-ce!26457

YouTrack docs review

Closes #58225

See merge request gitlab-org/gitlab-ce!26454

Clarify wiki permissions

Closes #53964

See merge request gitlab-org/gitlab-ce!23044

Start moving back to regular fe_docs
Remove Initiatives, add section to index in fe_guide
Delete some no-longer-relevant parts from principles
Update title - Progressive Enchancement is a browser-support term
and could be confused
"When to use" parts are discussed elswhere
Vue & jQuery issue is no longer relevant
Delete duplicate Security docs
Remove empty files, move event_tracking
Shuffle index sections around
Remove sections on Vue & Webpack (we say same thing in prev paragraph)
Remove link to Droplab docs