Add a few missing things on Windows, py310+ (#10817)

stdlib/msvcrt.pyi

@@ -26,3 +26,5 @@ if sys.platform == "win32":
     def ungetch(__char: bytes | bytearray) -> None: ...
     def ungetwch(__unicode_char: str) -> None: ...
     def heapmin() -> None: ...
+    if sys.version_info >= (3, 10):
+        def GetErrorMode() -> int: ...  # undocumented