Fix return type of tkinter.Text.search_all() (#15768)

Author: Akuli

stdlib/tkinter/__init__.pyi

@@ -3640,7 +3640,7 @@ class Text(Widget, XView, YView):
             nolinestop: bool | None = None,
             overlap: bool | None = None,
             strictlimits: bool | None = None,
-        ) -> tuple[str, ...]: ...
+        ) -> tuple[_tkinter.Tcl_Obj, ...]: ...
     else:
         def search(
             self,