Delete feature flag YAML file

Remove multi_select_board feature flag from FE and BE

Docs: try out suggestion-level substitutions

See merge request gitlab-org/gitlab!28060

Our current substitutions file in Vale is set to the error level,
which is not appropriate for all of the suggestions we want to make
to the technical writing team. This commit adds another substition
file with a name that makes clear the items within it are at a
suggestion level, rather than an error level.

Add helpful details to fixture error message

See merge request gitlab-org/gitlab!45826

The database fixtures for development can fail when the database is
being re-created without having deleted the old repositories from
Gitaly. This expands the error message to provide a hint about how
to fix that.

Add github host to API and clients

See merge request gitlab-org/gitlab!45188

Docs: Recommend multi-stage builds for efficient Docker image builds

See merge request gitlab-org/gitlab!46032

Add end-of-life status to docs styleguide

See merge request gitlab-org/gitlab!46274

Update GitLab Kubernetes Agent Server version

See merge request gitlab-org/gitlab!46282

Docs: Edited Maven topic

See merge request gitlab-org/gitlab!46072

Related to: https://gitlab.com/gitlab-org/gitlab/-/issues/247950

Fix empty icon for iteration system notes

See merge request gitlab-org/gitlab!45642

Clarify what happens during project repository storage moves

See merge request gitlab-org/gitlab!46083

Update Package docs to drive contributions

See merge request gitlab-org/gitlab!46287

Set defaults for cleanup policy regexes

See merge request gitlab-org/gitlab!44757

Fix filter comments e2e spec

See merge request gitlab-org/gitlab!45825

Adds checks to filter comments e2e spec and updates selectors

Add documentation for gitaly_ruby_json.log

See merge request gitlab-org/gitlab!46025

More realistic github import API example

See merge request gitlab-org/gitlab!46247

Remove admin_approval_for_new_user_signups feature flag

See merge request gitlab-org/gitlab!46051

Enable storage purchase link

See merge request gitlab-org/gitlab!46254

We might want to turn this off if we discover any issues
with CustomersDot

Remove Facet section from Issues workflow page

See merge request gitlab-org/gitlab!46271

Clarify mapping with self-managed imports

See merge request gitlab-org/gitlab!45817

Fix vulnerability details page not loading

See merge request gitlab-org/gitlab!46245

- it was expecting the request and response parameters
  to not exist, but the backend changed them so that
  they were null
- update tests

Normalize markdown source by removing UTF8 BOM character

See merge request gitlab-org/gitlab!46062

to remove UTF8 BOM character

Unquarantine snippet tests

See merge request gitlab-org/gitlab!46197

Make vulnerability filter template extensible and reusable

See merge request gitlab-org/gitlab!45863

Add `security_findings` table into the list of `HighTrafficTables`

See merge request gitlab-org/gitlab!45846

Fix transaction usage in ContainerExpirationPolicyWorker

See merge request gitlab-org/gitlab!46217