Deprecate widget flag: GTK_WIDGET_IS_SENSITIVE

Use gtk_widget_is_sensitive() instead

https://bugzilla.gnome.org/show_bug.cgi?id=69872

gtk/gtknotebook.c

@@ -3244,7 +3244,7 @@ static void
 gtk_notebook_state_changed (GtkWidget    *widget,
 			    GtkStateType  previous_state)
 {
-  if (!GTK_WIDGET_IS_SENSITIVE (widget)) 
+  if (!gtk_widget_is_sensitive (widget))
     stop_scrolling (GTK_NOTEBOOK (widget));
 }