Add multiple assignees to docs
New feature!
https://gitlab.com/gitlab-org/gitlab-ee/issues/1904
Add to Issues index page and Issues Functionalities page
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
New feature!
https://gitlab.com/gitlab-org/gitlab-ee/issues/1904
Add to Issues index page and Issues Functionalities page