patch 8.1.1421: drawing "~" line in popup window

Problem:    Drawing "~" line in popup window.
Solution:   Just draw text in the last line of the popup window.
diff --git a/src/version.c b/src/version.c
index 00eaacb..ca48793 100644
--- a/src/version.c
+++ b/src/version.c
@@ -768,6 +768,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1421,
+/**/
     1420,
 /**/
     1419,