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/edit.c b/src/edit.c
index c3aa888..0b0d174 100644
--- a/src/edit.c
+++ b/src/edit.c
@@ -4701,7 +4701,7 @@
 		|| old_topfill != curwin->w_topfill
 #endif
 		)
-	    redraw_later(VALID);
+	    redraw_later(UPD_VALID);
 	start_arrow(&tpos);
 	can_cindent = TRUE;
     }
@@ -4758,7 +4758,7 @@
 		|| old_topfill != curwin->w_topfill
 #endif
 		)
-	    redraw_later(VALID);
+	    redraw_later(UPD_VALID);
 	start_arrow(&tpos);
 	can_cindent = TRUE;
     }
@@ -5283,7 +5283,7 @@
 	    scrolldown_clamp();
 	else
 	    scrollup_clamp();
-	redraw_later(VALID);
+	redraw_later(UPD_VALID);
     }
     else
     {