patch 9.0.0512: cannot redraw the status lines when editing a command

Problem:    Cannot redraw the status lines when editing a command.
Solution:   Only postpone the redraw when messages have scrolled.
            (closes #11170)

src/version.c

@@ -699,6 +699,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    512,
 /**/
     511,
 /**/