[select] devpoll is @final (#15760)

Author: sobolevn

stdlib/select.pyi

@@ -159,6 +159,7 @@ if sys.platform == "linux":
 
 if sys.platform != "linux" and sys.platform != "darwin" and sys.platform != "win32":
     # Solaris only
+    @final
     class devpoll:
         def close(self) -> None: ...
         closed: bool