Use TypeAlias where possible for type aliases (#7630)

stdlib/reprlib.pyi

@@ -1,10 +1,11 @@
 from array import array
 from collections import deque
 from typing import Any, Callable
+from typing_extensions import TypeAlias
 
 __all__ = ["Repr", "repr", "recursive_repr"]
 
-_ReprFunc = Callable[[Any], str]
+_ReprFunc: TypeAlias = Callable[[Any], str]
 
 def recursive_repr(fillvalue: str = ...) -> Callable[[_ReprFunc], _ReprFunc]: ...