patch 9.0.0206: redraw flags are not named specifically

Problem:    Redraw flags are not named specifically.
Solution:   Prefix "UPD_" to the flags, for UPDate_screen().
diff --git a/src/menu.c b/src/menu.c
index bfad016..014d051 100644
--- a/src/menu.c
+++ b/src/menu.c
@@ -299,7 +299,7 @@
     root_menu_ptr = get_root_menu(menu_path);
     if (root_menu_ptr == &curwin->w_winbar)
 	// Assume the window toolbar menu will change.
-	redraw_later(NOT_VALID);
+	redraw_later(UPD_NOT_VALID);
 
     if (enable != MAYBE)
     {