Add notifications when a reblogged status has been updated (#17404)

* Add notifications when a reblogged status has been updated

* Change wording to say "edit" instead of "update" and add missing controls

* Replace previous update notifications with the most up-to-date one

config/locales/en.yml

@@ -1148,6 +1148,8 @@ en:
       title: New boost
     status:
       subject: "%{name} just posted"
+    update:
+      subject: "%{name} edited a post"
   notifications:
     email_events: Events for e-mail notifications
     email_events_hint: 'Select events that you want to receive notifications for:'