Add option to be notified when a followed user posts (#13546)

* Add bell button

Fix #4890

* Remove duplicate type from post-deployment migration

* Fix legacy class type mappings

* Improve query performance with better index

* Fix validation

* Remove redundant index from notifications

app/javascript/mastodon/actions/notifications.js

@@ -59,7 +59,7 @@ export function updateNotifications(notification, intlMessages, intlLocale) {
 
     let filtered = false;
 
-    if (notification.type === 'mention') {
+    if (['mention', 'status'].includes(notification.type)) {
       const dropRegex   = filters[0];
       const regex       = filters[1];
       const searchIndex = searchTextFromRawStatus(notification.status);