Use type hinting generics in standard collections (#19046)

aka PEP 585, added in Python 3.9

 - https://peps.python.org/pep-0585/
 - https://docs.astral.sh/ruff/rules/non-pep585-annotation/

tests/rest/admin/test_admin.py

@@ -20,7 +20,7 @@
 #
 
 import urllib.parse
-from typing import Dict, cast
+from typing import cast
 
 from parameterized import parameterized
 
@@ -65,7 +65,7 @@ class QuarantineMediaTestCase(unittest.HomeserverTestCase):
         room.register_servlets,
     ]
 
-    def create_resource_dict(self) -> Dict[str, Resource]:
+    def create_resource_dict(self) -> dict[str, Resource]:
         resources = super().create_resource_dict()
         resources["/_matrix/media"] = self.hs.get_media_repository_resource()
         return resources