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

stubs/urllib3/urllib3/_collections.pyi

@@ -1,4 +1,5 @@
 from collections.abc import MutableMapping
+from types import TracebackType
 from typing import Any, NoReturn, TypeVar
 
 _KT = TypeVar("_KT")
@@ -6,7 +7,9 @@ _VT = TypeVar("_VT")
 
 class RLock:
     def __enter__(self): ...
-    def __exit__(self, exc_type, exc_value, traceback): ...
+    def __exit__(
+        self, exc_type: type[BaseException] | None, exc_value: BaseException | None, traceback: TracebackType | None
+    ) -> None: ...
 
 class RecentlyUsedContainer(MutableMapping[_KT, _VT]):
     ContainerCls: Any

stubs/urllib3/urllib3/poolmanager.pyi

@@ -1,4 +1,6 @@
+from types import TracebackType
 from typing import Any
+from typing_extensions import Literal
 
 from .request import RequestMethods
 
@@ -8,7 +10,9 @@ class PoolManager(RequestMethods):
     pools: Any
     def __init__(self, num_pools=..., headers=..., **connection_pool_kw) -> None: ...
     def __enter__(self): ...
-    def __exit__(self, exc_type, exc_val, exc_tb): ...
+    def __exit__(
+        self, exc_type: type[BaseException] | None, exc_val: BaseException | None, exc_tb: TracebackType | None
+    ) -> Literal[False]: ...
     def clear(self): ...
     def connection_from_host(self, host, port=..., scheme=...): ...
     def connection_from_url(self, url): ...