ctypes errcheck type is wrong

[socketpair]

now: _ECT = Callable[[Optional[Type[_CData]], _FuncPointer, Tuple[_CData, ...]], _CData]

should be: _ECT = Callable[[Optional[_CData], _FuncPointer, Tuple[_CData, ...]], _CData]

Because, at least, the return type of this function must be the same as the first argument. And it should be an instance like c_int.