typing [nfc]: Use "notice" instead of "notification"

to avoid confusion with notifications for mobile apps.

Signed-off-by: Zixuan James Li <[email protected]>

Author: PIG208

lib/model/typing_status.dart

@@ -26,7 +26,7 @@ class TypingStatus extends ChangeNotifier {
     _timerMapsByNarrow[narrow]?.keys ?? [];
 
   // Using SendableNarrow as the key covers the narrows
-  // where typing notifications are supported (topics and DMs).
+  // where typing notices are supported (topics and DMs).
   final Map<SendableNarrow, Map<int, Timer>> _timerMapsByNarrow = {};
 
   @override