Room mentioning in the composer (#3868)

* refactored the suggestion item structure

to scale with the room pill

* Implemented a way for the rooms

to appear in the suggestions view for the RTE, however I need to add the pills to the composer and the compatibility with the plain text composer

* small code correction

* fix

* fixed a bug where the suggestion wasn't returning

the right suggestion type and the suggestion text properly

* implementation done!

also updated some tests, but we need more of them

* updated toolbar view model tests

* updated tests

* updated preview tests

* renamed the Avatars case for the suggestions

ElementX/Sources/Other/HTMLParsing/ElementXAttributeScope.swift

@@ -24,6 +24,11 @@ enum UserDisplayNameAttribute: AttributedStringKey {
     static var name = "MXUserDisplayNameAttribute"
 }
 
+enum RoomDisplayNameAttribute: AttributedStringKey {
+    typealias Value = String
+    static var name = "MXRoomDisplayNameAttribute"
+}
+
 enum RoomIDAttribute: AttributedStringKey {
     typealias Value = String
     static var name = "MXRoomIDAttribute"
@@ -64,6 +69,7 @@ extension AttributeScopes {
         
         let userID: UserIDAttribute
         let userDisplayName: UserDisplayNameAttribute
+        let roomDisplayName: RoomDisplayNameAttribute
         let roomID: RoomIDAttribute
         let roomAlias: RoomAliasAttribute
         let eventOnRoomID: EventOnRoomIDAttribute