Add type annotations for **options in tkinter.messagebox functions (#14341)

Co-authored-by: Akuli <akuviljanen17@gmail.com>

stdlib/tkinter/commondialog.pyi

@@ -11,4 +11,4 @@ class Dialog:
     # sometimes changed to a different type.
     options: Mapping[str, Any]
     def __init__(self, master: Misc | None = None, **options: Any) -> None: ...
-    def show(self, **options: Any): ...
+    def show(self, **options: Any) -> Any: ...