Remove fallback replies & implement intentional mentions (#2138)

* Remove reply fallbacks & add m.mentions

(WIP) the typing on line 301 and 303 needs fixing but apart from that this is mint

* Less jank typing

* Mention the reply author in m.mentions

* Improve typing

* Fix typing in m.mentions finder

* Correctly iterate through editor children, properly handle @room, ...

..., don't mention the reply author when the reply author is ourself, don't add own user IDs when mentioning intentionally

* Formatting

* Add intentional mentions to edited messages

* refactor reusable code and fix todo

* parse mentions from all nodes

---------

Co-authored-by: Ajay Bura <32841439+ajbura@users.noreply.github.com>

src/app/utils/room.ts

@@ -4,6 +4,7 @@ import {
   EventTimeline,
   EventTimelineSet,
   EventType,
+  IMentions,
   IPushRule,
   IPushRules,
   JoinRule,
@@ -430,3 +431,15 @@ export const getLatestEditableEvt = (
 export const reactionOrEditEvent = (mEvent: MatrixEvent) =>
   mEvent.getRelation()?.rel_type === RelationType.Annotation ||
   mEvent.getRelation()?.rel_type === RelationType.Replace;
+
+export const getMentionContent = (userIds: string[], room: boolean): IMentions => {
+  const mMentions: IMentions = {};
+  if (userIds.length > 0) {
+    mMentions.user_ids = userIds;
+  }
+  if (room) {
+    mMentions.room = true;
+  }
+
+  return mMentions;
+};