Document removing approval.

doc/user/project/merge_requests/merge_request_approvals.md

@@ -68,6 +68,16 @@ assign several users with one action. One possible scenario would be to to assig
 a group of approvers at the project level and change them later when creating
 or editing the merge request.
 
+## Removing approval
+
+A designated approver can remove their approval at any time. If, when an approver
+removes their approval, the number of approvals given falls below the number of
+required approvals, the merge request cannot be accepted.
+
+If, on the other hand, an approver removes their approval but the number of approvals
+given stays at or above the number of required approvals, the merge request can still be
+accepted.
+
 ## Using approvals
 
 After configuring approvals, you will be able to change the default set of
@@ -93,3 +103,7 @@ will be decreased by one.
 ![Merge request approval](img/approvals_mr_approved.png)
 
 [ee-743]: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/743
+
+To remove approval, just press the **Remove your approval** button
+
+![Merge request remove approval](img/remove_approval_mr.png)

doc/workflow/notifications.md

@@ -88,11 +88,12 @@ In all of the below cases, the notification will be sent to:
 | Close merge request    | |
 | Reopen merge request   | |
 | Merge merge request    | |
+| Approved merge request | |
+| Unapproved merge request | |
 | New comment            | The above, plus anyone mentioned by `@username` in the comment, with notification level "Mention" or higher |
 | Failed pipeline        | The above, plus the author of the pipeline |
 | Successful pipeline    | The above, plus the author of the pipeline |
 
-
 In addition, if the title or description of an Issue or Merge Request is
 changed, notifications will be sent to any **new** mentions by `@username` as
 if they had been mentioned in the original text.