Add some missing type hints to tkinter (#6359)

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

stdlib/tkinter/tix.pyi

@@ -45,7 +45,7 @@ class tixCommand:
     def tix_resetoptions(self, newScheme: str, newFontSet: str, newScmPrio: str | None = ...) -> None: ...
 
 class Tk(tkinter.Tk, tixCommand):
-    def __init__(self, screenName: str | None = ..., baseName: str | None = ..., className: str = ...): ...
+    def __init__(self, screenName: str | None = ..., baseName: str | None = ..., className: str = ...) -> None: ...
 
 class TixWidget(tkinter.Widget):
     def __init__(