Add shortcut tooltips to work items

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/183757



Merged-by: Deepika Guliani <dguliani@gitlab.com>
Approved-by: Deepika Guliani <dguliani@gitlab.com>
Reviewed-by: Deepika Guliani <dguliani@gitlab.com>
Co-authored-by: Nick Leonard <nleonard@gitlab.com>