docs(en/recipes/multi_isolate): fix code comment

docs/docs/recipes/multi_isolate.md

@@ -58,7 +58,7 @@ Future createDummyMessages(int count) async {
   );
 
   final messages = List.generate(count, (i) => Message()..content = 'Message $i');
-  // we use a synchronous transactions in isolates
+  // we use synchronous transactions in isolates
   isar.writeTxnSync(() {
     isar.messages.insertAllSync(messages);
   });