Improve many __(a)exit__ annotations (#9696)

stubs/JACK-Client/jack/__init__.pyi

@@ -1,4 +1,5 @@
 import sys
+from _typeshed import Unused
 from collections.abc import Callable, Generator, Iterable, Iterator, Sequence
 from typing import Any, NoReturn, overload
 from typing_extensions import Literal, Self
@@ -80,7 +81,7 @@ class Client:
         session_id: str | None = ...,
     ) -> None: ...
     def __enter__(self) -> Self: ...
-    def __exit__(self, *args: object) -> None: ...
+    def __exit__(self, *args: Unused) -> None: ...
     @property
     def name(self) -> str: ...
     @property