Update typing_extensions imports in stdlib (#11244)

Co-authored-by: AlexWaygood <alex.waygood@gmail.com>

stdlib/syslog.pyi

@@ -1,6 +1,5 @@
 import sys
-from typing import overload
-from typing_extensions import Literal
+from typing import Literal, overload
 
 if sys.platform != "win32":
     LOG_ALERT: Literal[1]