Because the post-processing of the rendered README is dependent on the
context (i.e. the current user), do the post-processing when the
README is being displayed.

It does more than solely GitLab Markdown, so rename to MarkupHelper.

Add username to activity atom feed

Closes #31268

See merge request !10802

See pull request https://github.com/gitlabhq/gitlabhq/pull/10429

Remove description for build_events, add pipeline_events

Closes #30645

See merge request !10908

Fix typo found in issue board sidebar milestone dropdown

Closes #31475

See merge request !10950

Update troubleshooting section

Closes #13479

See merge request !10618

don't require no_root_squash on NFS, only recommend

See merge request !10197

clarify when GitLab pages requires special config for load balancer

See merge request !10954

Fix Rubocop CyclomaticComplexity offense

See merge request !10941

Add button to delete filters from filtered search bar

Closes #30466

See merge request !10795

Fix a failing Rubocop rule on master

Closes #31458

See merge request !10947

Add GitLab version to backup file name

See merge request !10901

Bump Sidekiq to 5.0.0

See merge request !10943

correct documentation on opt-out-ness of usage ping

See merge request !10945

Resolve "Jobs dropdown in mini graph should close when we receive an error"

Closes #31335

See merge request !10887

http://rubular.com/r/op7TI9UX6K

Submodule Dockerfile templates

See merge request !10663

Replace header merge request icon

Closes #31088

See merge request !10932

Use rspec-set to speed up examples

See merge request !10551