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.

Remove CREATE_DB_USER variable in prepare_build

See merge request gitlab-org/gitlab-ce!23815

Update prettier.md with VSCode Settings section

See merge request gitlab-org/gitlab-ce!23810

When this spec is run in a certain order, there appeared to be a timing
issue with opening the "Merge when pipeline succeeds" drop-down menu. We
now explicitly wait for any pending requests to complete before clicking
the drop-down.

Closes https://gitlab.com/gitlab-org/gitlab-ee/issues/6770

Fix warnings in tests

See merge request gitlab-org/gitlab-ce!23788

Refactor Ci::Pipeline's config_sources enum

Closes gitlab-ee#8244

See merge request gitlab-org/gitlab-ce!23799

Move description of cluster type to presenter

Closes #53771

See merge request gitlab-org/gitlab-ce!23789

Remove issue_suggestions feature flag

Closes #55166

See merge request gitlab-org/gitlab-ce!23723

Update changelog to include Merge Request ID and Author

Update changelog to include Merge Request ID and Author

**Why?**

This is a recurring issue that new team members keep running into.

doc/ci/yaml: improve wording to explain better deep vs recursive merging

See merge request gitlab-org/gitlab-ce!22542

Serverless Doc Updates

Closes #55089

See merge request gitlab-org/gitlab-ce!23640

All arguments passed to the `FeatureConstrainer` will be passed on to
the `Feature.enabled?` check.

Add dplanella as Catalan proofreader

See merge request gitlab-org/gitlab-ce!23827

Docs add empty space to render list

See merge request gitlab-org/gitlab-ce!23756

Docs: Align CE and EE k8s doc to match

Closes #54771

See merge request gitlab-org/gitlab-ce!23758

Add name, author and sha to releases

See merge request gitlab-org/gitlab-ce!23763

Display reply field if resolved discussion has no replies

Closes #54330

See merge request gitlab-org/gitlab-ce!23801

Stop using HipChat in the ServicesController spec

See merge request gitlab-org/gitlab-ce!23774

Creates Vue component to render each release block

See merge request gitlab-org/gitlab-ce!23697

Resolve "Only prompt user once when navigating away from file editor"

Closes #55344

See merge request gitlab-org/gitlab-ce!23820

Upgrade Knative from 0.1.3 to 0.2.2

See merge request gitlab-org/gitlab-ce!23808