Remove rails4 specific code

See merge request gitlab-org/gitlab-ce!23847

Clearly state web terminal is not supported at all on GitLab.com

See merge request gitlab-org/gitlab-ce!23821

Show clusters of ancestors in cluster list page

Closes #34758

See merge request gitlab-org/gitlab-ce!22996

Resolve "Encoding issue with the user centric tooltips"

Closes #55276

See merge request gitlab-org/gitlab-ce!23794

Passing the separator argument as a positional parameter is deprecated

See merge request gitlab-org/gitlab-ce!23334

Added Cop for injecting EE modules

See merge request gitlab-org/gitlab-ce!23802

CE-EE parity for prepare_build script

See merge request gitlab-org/gitlab-ce!23819

Add Registry S3 chunksize troubleshooting section

See merge request gitlab-org/gitlab-ce!23841

Fix RSpec/HookArgument rubocop offense

See merge request gitlab-org/gitlab-ce!23776

Given the note is about how to interpret ancestor clusters, use the
finder which actually knows if there are any ancestor clusters to find
out if the note should be shown, rather than passing the same info via a
view to a helper

Added note about Kaminari.paginate_array

Link to followup issue too

This is in addtion to the can checks we have in the controller, as a
finder can be used elsewhere in the future.

Part of the code such as #show_path is already present on the presenter.
Also avoid having code in two places (helper and presenter)

Sanitize and assert html_safe. Additional layer of defense - on top of
GitLab already requiring group names to be composed of small set of
chars A-Z, - and spaces.

Only link to cluster if user can read cluster

Make clear that arg is a GroupClusterablePresenter

Add more specs for completeness

- Use sprite_icon instead of hardcoded html
- Use a more descriptive method name
- Changes specs to use html_safe matcher

- Moves logic into ClustersHelp
- Add CSS to ensure compatibility with EE view.

Add specs

Make link clear in note box

Also update strings to be translatable

Show both the cluster(s) of the clusterable, and the cluster(s) of
ancestor groups.

Merge branch '55402-broken-master-karma-test-failing-in-spec-javascripts-boards-components-issue_due_date_spec-js' into 'master'

Resolve "Broken master: karma test failing in spec/javascripts/boards/components/issue_due_date_spec.js"

Closes #55402

See merge request gitlab-org/gitlab-ce!23845

Display empty files properly on MR diffs

Closes #54786

See merge request gitlab-org/gitlab-ce!23671

Resolve transient failure in Help page spec

Closes #55372

See merge request gitlab-org/gitlab-ce!23839

Resolve "Merge button does not appear after Rebase-ing"

Closes #47052

See merge request gitlab-org/gitlab-ce!23572

Fixed link in doc/ci/yaml/README.md

See merge request gitlab-org/gitlab-ce!23433

Refactor the only and except complex section

See merge request gitlab-org/gitlab-ce!23792

Docs: Let's Encrypt certificate for GitLab Pages

Closes #51979

See merge request gitlab-org/gitlab-ce!23777

Removed rails 5 documentation

See merge request gitlab-org/gitlab-ce!23840

Remove Rails 4 support

See merge request gitlab-org/gitlab-ce!23717

Resolve a transient failure in MWPS feature spec

Closes gitlab-ee#6770

See merge request gitlab-org/gitlab-ce!23838

Sometimes due to a slow request to load the version check image, the
placeholder image data was still being seen, resulting in this failure:

    expected "data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" to end with "/version-check-url"

Now we check the `data-src` attribute, which allows us to remove the
`:js` metadata.

This commit also removes a redundant test, which was just ensuring that
the selector we were already using in the other test is visible. If this
test were failing, the other one would always fail too, so it was
pointless.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/55372

All of these methods are stateless, there was no point to have them as
instance methods.

Mostly this allows us to remove an `allow_any_instance_of` usage.

Because we removed rails 4 support, this document is not needed
anymore.