Fix sphinx-doc#9589: autodoc: typing.Annotated has wrongly been rendered

At the HEAD of 3.10, the implementation of `typing.Annotated` has
been changed to have __qualname__.

sphinx/util/typing.py

@@ -306,6 +306,8 @@ def stringify(annotation: Any) -> str:
         return 'None'
     elif annotation in INVALID_BUILTIN_CLASSES:
         return INVALID_BUILTIN_CLASSES[annotation]
+    elif str(annotation).startswith('typing.Annotated'):  # for py310+
+        pass
     elif (getattr(annotation, '__module__', None) == 'builtins' and
           getattr(annotation, '__qualname__', None)):
         return annotation.__qualname__