Use PEP 604 syntax wherever possible (#7493)

stubs/aiofiles/aiofiles/os.pyi

@@ -2,11 +2,11 @@ import sys
 from _typeshed import StrOrBytesPath
 from asyncio.events import AbstractEventLoop
 from os import stat_result
-from typing import Any, Sequence, Union, overload
+from typing import Any, Sequence, overload
 
 from . import ospath as path
 
-_FdOrAnyPath = Union[int, StrOrBytesPath]
+_FdOrAnyPath = int | StrOrBytesPath
 
 async def stat(
     path: _FdOrAnyPath,  # noqa: F811

stubs/aiofiles/aiofiles/threadpool/__init__.pyi

@@ -7,14 +7,14 @@ from _typeshed import (
     StrOrBytesPath,
 )
 from asyncio import AbstractEventLoop
-from typing import Any, Callable, Union, overload
+from typing import Any, Callable, overload
 from typing_extensions import Literal
 
 from ..base import AiofilesContextManager
 from .binary import AsyncBufferedIOBase, AsyncBufferedReader, AsyncFileIO, _UnknownAsyncBinaryIO
 from .text import AsyncTextIOWrapper
 
-_OpenFile = Union[StrOrBytesPath, int]
+_OpenFile = StrOrBytesPath | int
 _Opener = Callable[[str, int], int]
 
 # Text mode: always returns AsyncTextIOWrapper