stdlib: audit more callback annotations (#8209)

stdlib/wsgiref/validate.pyi

@@ -1,6 +1,7 @@
 from _typeshed.wsgi import ErrorStream, InputStream, WSGIApplication
 from collections.abc import Callable, Iterable, Iterator
 from typing import Any, NoReturn
+from typing_extensions import TypeAlias
 
 __all__ = ["validator"]
 
@@ -25,9 +26,11 @@ class ErrorWrapper:
     def writelines(self, seq: Iterable[str]) -> None: ...
     def close(self) -> NoReturn: ...
 
+_WriterCallback: TypeAlias = Callable[[bytes], Any]
+
 class WriteWrapper:
-    writer: Callable[[bytes], Any]
-    def __init__(self, wsgi_writer: Callable[[bytes], Any]) -> None: ...
+    writer: _WriterCallback
+    def __init__(self, wsgi_writer: _WriterCallback) -> None: ...
     def __call__(self, s: bytes) -> None: ...
 
 class PartialIteratorWrapper: