Merge branch 'Update-roadmap-doc-per-212494' into 'master'

Update roadmap docs for collapsible milestones

See merge request gitlab-org/gitlab!36154

doc/user/group/roadmap/index.md

@@ -13,6 +13,7 @@ info: To determine the technical writer assigned to the Stage/Group associated w
 > - Milestones appear in roadmaps in [GitLab 12.10](https://gitlab.com/gitlab-org/gitlab/-/issues/6802), and later.
 > - Feature flag for milestones visible in roadmaps removed in [GitLab 13.0](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/29641).
 > - In [GitLab 13.2](https://gitlab.com/gitlab-org/gitlab/-/issues/214375) and later, the Roadmap also shows milestones in projects in a group.
+> - In [GitLab 13.2](https://gitlab.com/gitlab-org/gitlab/-/issues/212494) and later, milestone bars can be collapsed and expanded.
 
 Epics and milestones within a group containing a start date or due date can be visualized in a form
 of a timeline (that is, a Gantt chart). The Roadmap page shows the epics and milestones in a
@@ -23,11 +24,12 @@ When you hover over an epic bar, a popover appears with the epic's title, start
 weight completed.
 
 You can expand epics that contain child epics to show their child epics in the roadmap.
-You can click the chevron **{chevron-down}** next to the epic title to expand and collapse the child epics.
+You can click the chevron (**{chevron-down}**) next to the epic title to expand and collapse the child epics.
 
 On top of the milestone bars, you can see their title. When you hover a milestone bar or title, a popover appears with its title, start date and due date.
+You can also click the chevron (**{chevron-down}**) next to the **Milestones** heading to toggle the list of the milestone bars.
 
-![roadmap view](img/roadmap_view_v13_0.png)
+![roadmap view](img/roadmap_view_v13_2.png)
 
 A dropdown menu allows you to show only open or closed epics. By default, all epics are shown.