Merge branch 'docs/issue-to-epic' into 'master'

Mention how to promote an issue to an epic

Closes #8860

See merge request gitlab-org/gitlab-ee!8905

doc/user/group/epics/index.md

@@ -93,11 +93,24 @@ link in the issue sidebar.
 
 ## Promoting an issue to an epic
 
-A user who has permissions to close an issue and create an epic in the parent group
-can promote an issue to an epic.
-The epic is created in the group the issue project belongs to (direct parent group).
+> [Introduced](https://gitlab.com/gitlab-org/gitlab-ee/issues/7730) in [GitLab Ultimate](https://about.gitlab.com/pricing/) 10.6.
+
+If you have [permissions](../../permissions.md) to close an issue and create an
+epic in the parent group, you can promote an issue to an epic with the `/promote`
+[quick action](../../project/quick_actions.md#quick-actions-for-epics-ultimate).
 Only issues from projects that are in groups can be promoted.
 
+Once the quick action is applied, the epic will be created in the group the
+issue of the project belongs to (direct parent group). A notification of that
+epic creation will be sent to the subscribers of the original issue.
+
+The following issue metadata will be copied to the epic:
+
+- Title, description, activity/comment thread
+- Upvotes/downvotes
+- Participants
+- Group labels that the issue already has
+
 ## Searching for an epic from epics list page
 
 > Introduced in [GitLab Ultimate][ee] 10.5.