TYP: Annotate numpy.bool.__index__ and mark as deprecated

Author: jorenham

numpy/__init__.pyi

@@ -3292,7 +3292,8 @@ class bool(_RealMixin, generic):
     def __init__(self, value: object = ..., /) -> None: ...
     def item(self, args: L[0] | tuple[()] | tuple[L[0]] = ..., /) -> builtins.bool: ...
     def tolist(self) -> builtins.bool: ...
-
+    @deprecated("In future, it will be an error for 'np.bool' scalars to be interpreted as an index")
+    def __index__(self, /) -> int: ...
     def __abs__(self) -> Self: ...
     __add__: _BoolOp[np.bool]
     __radd__: _BoolOp[np.bool]