Update docs to show approvers no longer added as participants by default

doc/user/profile/notifications.md

@@ -159,6 +159,9 @@ In most of the below cases, the notification will be sent to:
 - Subscribers: anyone who manually subscribed to the issue, merge request, or epic **(ULTIMATE)**
 - Custom: Users with notification level "custom" who turned on notifications for any of the events present in the table below
 
+NOTE: **Note:**
+To minimize the number of notifications that do not require any action, from [GitLab 12.9 onwards](https://gitlab.com/gitlab-org/gitlab/issues/616), eligible approvers are no longer notified for all the activities in their projects. To receive them they have to change their user notification settings to **Watch** instead.
+
 | Event                  | Sent to |
 |------------------------|---------|
 | New issue              |         |