Remove the is_announcement docstring

synapse/handlers/sync.py

@@ -277,9 +277,6 @@ class JoinedSyncResult:
     summary: JsonDict | None
     unread_count: int
     is_announcement: bool = False
-    """Unread counts are always zero for announcement rooms: push actions are only
-    computed for members, and computing the counts fails for a user with no
-    membership in the room."""
 
     def __bool__(self) -> bool:
         """Make the result appear empty if there are no updates. This is used