Audit stdlib object annotations (#9519)

stdlib/cgi.pyi

@@ -1,5 +1,5 @@
 import sys
-from _typeshed import Self, SupportsGetItem, SupportsItemAccess
+from _typeshed import Self, SupportsGetItem, SupportsItemAccess, Unused
 from builtins import list as _list, type as _type
 from collections.abc import Iterable, Iterator, Mapping
 from email.message import Message
@@ -106,7 +106,7 @@ class FieldStorage:
         separator: str = ...,
     ) -> None: ...
     def __enter__(self: Self) -> Self: ...
-    def __exit__(self, *args: object) -> None: ...
+    def __exit__(self, *args: Unused) -> None: ...
     def __iter__(self) -> Iterator[str]: ...
     def __getitem__(self, key: str) -> Any: ...
     def getvalue(self, key: str, default: Any = ...) -> Any: ...