Update docs for Milestones in Roadmap

doc/user/group/roadmap/index.md

@@ -6,24 +6,28 @@ type: reference
 
 > - Introduced in [GitLab Ultimate](https://about.gitlab.com/pricing/) 10.5.
 > - In [GitLab 12.9](https://gitlab.com/gitlab-org/gitlab/issues/198062), Roadmaps were moved to the Premium tier.
-> - In [GitLab 12.9](https://gitlab.com/gitlab-org/gitlab/issues/5164) and later, the epic bars show their title, progress, and completed weight percentage.
+> - In [GitLab 12.9](https://gitlab.com/gitlab-org/gitlab/issues/5164) and later, the epic bars show epics' title, progress, and completed weight percentage.
+> - In [GitLab 12.10](https://gitlab.com/gitlab-org/gitlab/-/issues/6802), and later, milestones appear in Roadmaps.
 
-An Epic within a group containing **Start date** and/or **Due date**
-can be visualized in a form of a timeline (a Gantt chart). The Epics Roadmap page
-shows such a visualization for all the epics which are under a group and/or its subgroups.
+Epics and milestones within a group containing **Start date** and/or **Due date**
+can be visualized in a form of a timeline (that is, a Gantt chart). The Roadmap page
+shows such a visualization for all the epics and milestones which are under a group or one of its
+subgroups.
 
-On the epic bars, you can see their title, progress, and completed weight percentage.
-When you hover over an epic bar, a popover appears with its title, start and due dates, and weight
-completed.
+On the epic bars, you can see the each epic's title, progress, and completed weight percentage.
+When you hover over an epic bar, a popover appears with the epic's title, start date, due date, and
+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.
 
-![roadmap view](img/roadmap_view_v12_9.png)
+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.
+
+![roadmap view](img/roadmap_view_v12_10.png)
 
 A dropdown menu allows you to show only open or closed epics. By default, all epics are shown.
 
-![epics state dropdown](img/epics_state_dropdown.png)
+![epics state dropdown](img/epics_state_dropdown_v12_10.png)
 
 You can sort epics in the Roadmap view by:
 
@@ -32,8 +36,8 @@ You can sort epics in the Roadmap view by:
 - Start date
 - Due date
 
-Each option contains a button that toggles the sort order between **ascending** and **descending**. The sort option and order will be persisted when browsing Epics,
-including the [epics list view](../epics/index.md).
+Each option contains a button that toggles the sort order between **ascending** and **descending**.
+The sort option and order persist when browsing Epics, including the [epics list view](../epics/index.md).
 
 Roadmaps can also be [visualized inside an epic](../epics/index.md#roadmap-in-epics).
 
@@ -45,15 +49,16 @@ Roadmaps can also be [visualized inside an epic](../epics/index.md#roadmap-in-ep
 Roadmap supports the following date ranges:
 
 - Quarters
-- Months (Default)
+- Months (default)
 - Weeks
 
 ### Quarters
 
 ![roadmap date range in quarters](img/roadmap_timeline_quarters.png)
 
-In _Quarters_ preset, roadmap shows epics which have start or due dates _falling within_ or
-_going through_ **past quarter**, **current quarter** and **next 4 quarters**, where _today_
+In the **Quarters** preset, roadmap shows epics and milestones which have start or due dates
+**falling within** or **going through** past quarter, current quarter, and the next four quarters,
+where **today**
 is shown by the vertical red line in the timeline. The sub-headers underneath the quarter name on
 the timeline header represent the month of the quarter.
 
@@ -61,8 +66,9 @@ the timeline header represent the month of the quarter.
 
 ![roadmap date range in months](img/roadmap_timeline_months.png)
 
-In _Months_ preset, roadmap shows epics which have start or due dates _falling within_ or
-_going through_ **past month**, **current month** and **next 5 months**, where _today_
+In the **Months** preset, roadmap shows epics and milestones which have start or due dates
+**falling within** or
+**going through** the past month, current month, and the next five months, where **today**
 is shown by the vertical red line in the timeline. The sub-headers underneath the month name on
 the timeline header represent the date on starting day (Sunday) of the week. This preset is
 selected by default.
@@ -71,14 +77,15 @@ selected by default.
 
 ![roadmap date range in weeks](img/roadmap_timeline_weeks.png)
 
-In _Weeks_ preset, roadmap shows epics which have start or due dates _falling within_ or
-_going through_ **past week**, **current week** and **next 4 weeks**, where _today_
+In the **Weeks** preset, roadmap shows epics and milestones which have start or due dates **falling
+within** or **going through** the past week, current week and the next four weeks, where **today**
 is shown by the vertical red line in the timeline. The sub-headers underneath the week name on
 the timeline header represent the days of the week.
 
-## Timeline bar for an epic
+## Roadmap timeline bar
 
-The timeline bar indicates the approximate position of an epic based on its start and due date.
+The timeline bar indicates the approximate position of an epic or milestone based on its start and
+due dates.
 
 <!-- ## Troubleshooting