Merge branch 'docs-repo-merge-12-user-disc-ee' into 'master'

Docs: (EE Port) Merge EE doc/​user/discussions to CE

See merge request gitlab-org/gitlab-ee!11650

doc/user/discussions/index.md

@@ -5,7 +5,7 @@ The ability to contribute conversationally is offered throughout GitLab.
 You can leave a comment in the following places:
 
 - issues
-- epics
+- epics **[ULTIMATE]**
 - merge requests
 - snippets
 - commits