Fix epic bar title text

Epic bars were incorrectly displaying the description
instead of the title

doc/user/group/roadmap/index.md

@@ -14,7 +14,7 @@ shows such a visualization for all the epics which are under a group and/or its
 > [Introduced](https://gitlab.com/gitlab-org/gitlab/issues/5164) in GitLab 12.9.
 
 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 description, start and due dates, and weight completed.
+When you hover over an epic bar, a popover appears with its title, start and due dates, and weight completed.
 
 ![roadmap view](img/roadmap_view_v12_9.png)
 

ee/app/assets/javascripts/roadmap/components/epic_item_timeline.vue

@@ -191,7 +191,7 @@ export default {
       </a>
       <gl-popover
         :target="`epic-bar-${epic.id}`"
-        :title="epic.description"
+        :title="epic.title"
         triggers="hover focus"
         placement="right"
       >