fixup! Add regression test from typeddjango#2304

Author: flaeppe

tests/typecheck/managers/test_managers.yml

@@ -679,7 +679,7 @@
 -   case: test_objects_managers_is_kept_with_specific_import_graph
     main: |
         from zerver.models import RealmFilter
-        reveal_type(RealmFilter.objects)
+        reveal_type(RealmFilter.objects)  # N: Revealed type is "django.db.models.manager.Manager[zerver.models.linkifiers.RealmFilter]"
     installed_apps:
         - django.contrib.auth
         - django.contrib.contenttypes