Resolve "Email notifications not sent as expected"

Closes #38862

See merge request gitlab-org/gitlab-ce!15686

Fix typo in Elasticsearch

Closes #40770

See merge request gitlab-org/gitlab-ce!15699

For a user with the mention notification level set, the type of their
corresponding NotificationRecipient must be :mention for them to receive an
email.

We set this correctly on notes, but we weren't adding it on new issues or MRs -
perhaps because these users are also participants. But the type of the
NotificationRecipient in that case would be :participant, not mention, so we
have to add the mentioned users manually when creating an issue or MR.

When editing an issue or MR, and there are newly-mentioned users to email, we
still use the :new_issue and :new_merge_request actions, so this works for that
case as well.

Fix the fork project functionality for projects with hashed storage

Closes #40711

See merge request gitlab-org/gitlab-ce!15671

Add version that the mermaid support was introduced

See merge request gitlab-org/gitlab-ce!15688

Add underline hover state to all links

Closes #24129

See merge request gitlab-org/gitlab-ce!15638

Keep track of all storage keys in a set

See merge request gitlab-org/gitlab-ce!15613

Added default order to UserFinder

Closes #40407

See merge request gitlab-org/gitlab-ce!15679

Note the dependency on gitlab-shell v5.10.0

Don't disable the Rails mailer when seeding the test environment

See merge request gitlab-org/gitlab-ce!15690

Documentation bug fixes: Added procedure to disable built-in Issues.

See merge request gitlab-org/gitlab-ce!15581

Merge branch '40746-broken-master-due-to-failure-in-spec-services-clusters-applications-schedule_installation_service_spec-rb' into 'master'

Ensure `Namespace`'s is namespaced in `Gitlab::Kubernetes::Helm#initialize` and fix a transient failing spec due to that

Closes #40746

See merge request gitlab-org/gitlab-ce!15684

That way we don't need the to scan the entire keyspace to get all
known keys

Ensure `Namespace`'s is namespaced in `Gitlab::Kubernetes::Helm#initialize` and fix a transient failing spec due to that
Signed-off-by: Rémy Coutable <remy@rymai.me>

Show only group name by default and put full namespace in tooltip in Groups tree

Closes #40286

See merge request gitlab-org/gitlab-ce!15650

Extract class responsible for building a pipeline

Closes #38460

See merge request gitlab-org/gitlab-ce!14762

Adds validation for Project#ci_config_path not to contain leading slash

Closes #34683

See merge request gitlab-org/gitlab-ce!15672

Gracefully handle case when repository's root ref does not exist

Closes #40615

See merge request gitlab-org/gitlab-ce!15678

Set EE variable for package build triggers from GitLab EE repository

Closes omnibus-gitlab#3006

See merge request gitlab-org/gitlab-ce!15677

This was failing regularly with an Error 500 when the API branches endpoint
was used.

Closes #40615

Clean up Capybara configuration

Closes #40599

See merge request gitlab-org/gitlab-ce!15644

issue note store

See merge request gitlab-org/gitlab-ce!15657

Align Select2 search field

Closes #39451

See merge request gitlab-org/gitlab-ce!15048

allow caching options to be specified for counting services

See merge request gitlab-org/gitlab-ce!15651

Improve require input spec

See merge request gitlab-org/gitlab-ce!15654

Add project_members controller when not signed in

Closes #40642

See merge request gitlab-org/gitlab-ce!15659

[ci skip]

Add link to Gitaly conversion

[ci skip]

See merge request gitlab-org/gitlab-ce!15666