Add alt_aliases to room completion candidates

but don't match on name otherwise you see multiple entries per room
when searching for a room name

Also pass the roomId to the composer autocomplete, so
it's easier to we don't need to loop through all the rooms and
it's also easier accept room with local aliases as well in the future

src/editor/autocomplete.js

@@ -102,7 +102,7 @@ export default class AutocompleteWrapperModel {
         const text = completion.completion;
         switch (completion.type) {
             case "room":
-                return [this._partCreator.roomPill(completionId), this._partCreator.plain(completion.suffix)];
+                return [this._partCreator.roomPill(text, completionId), this._partCreator.plain(completion.suffix)];
             case "at-room":
                 return [this._partCreator.atRoomPill(completionId), this._partCreator.plain(completion.suffix)];
             case "user":