Use TypeAlias where possible for type aliases (#7630)

stubs/docopt/docopt.pyi

@@ -1,8 +1,9 @@
 from typing import Any, Iterable
+from typing_extensions import TypeAlias
 
 __version__: str
 
-_Argv = Iterable[str] | str
+_Argv: TypeAlias = Iterable[str] | str
 
 def docopt(
     doc: str, argv: _Argv | None = ..., help: bool = ..., version: Any | None = ..., options_first: bool = ...