Stdlib: add many missing __hash__ and __eq__ methods (#10464)

stdlib/contextvars.pyi

@@ -18,6 +18,7 @@ class ContextVar(Generic[_T]):
     def __init__(self, name: str) -> None: ...
     @overload
     def __init__(self, name: str, *, default: _T) -> None: ...
+    def __hash__(self) -> int: ...
     @property
     def name(self) -> str: ...
     @overload
@@ -60,3 +61,4 @@ class Context(Mapping[ContextVar[Any], Any]):
     def __getitem__(self, __key: ContextVar[_T]) -> _T: ...
     def __iter__(self) -> Iterator[ContextVar[Any]]: ...
     def __len__(self) -> int: ...
+    def __eq__(self, __value: object) -> bool: ...