Make 'unmarked as WIP' message more consistent

app/services/system_note_service.rb

@@ -146,7 +146,7 @@ module SystemNoteService
   end
   def remove_merge_request_wip(noteable, project, author)
-    body = 'unmarked as a Work In Progress'
+    body = 'unmarked as a **Work In Progress**'
     create_note(noteable: noteable, project: project, author: author, note: body)
   end