Use _typeshed.Self in docutils.VersionInfo and os.sched_param (#7117)

stdlib/os/__init__.pyi

@@ -953,7 +953,7 @@ else:
 if sys.platform != "win32":
     @final
     class sched_param(structseq[int], tuple[int]):
-        def __new__(cls, sched_priority: int) -> sched_param: ...
+        def __new__(cls: type[Self], sched_priority: int) -> Self: ...
         @property
         def sched_priority(self) -> int: ...