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/fold.c b/src/fold.c
index ee94a97..83d1cf6 100644
--- a/src/fold.c
+++ b/src/fold.c
@@ -413,7 +413,7 @@
 	emsg(_(e_no_fold_found));
     // Force a redraw to remove the Visual highlighting.
     if (had_visual)
-	redraw_curbuf_later(INVERTED);
+	redraw_curbuf_later(UPD_INVERTED);
 }
 
 // openFold() {{{2
@@ -786,7 +786,7 @@
 	emsg(_(e_no_fold_found));
 	// Force a redraw to remove the Visual highlighting.
 	if (had_visual)
-	    redraw_curbuf_later(INVERTED);
+	    redraw_curbuf_later(UPD_INVERTED);
     }
     else
 	// Deleting markers may make cursor column invalid.
@@ -875,7 +875,7 @@
 foldUpdateAll(win_T *win)
 {
     win->w_foldinvalid = TRUE;
-    redraw_win_later(win, NOT_VALID);
+    redraw_win_later(win, UPD_NOT_VALID);
 }
 
 // foldMoveTo() {{{2