patch 8.1.1666: click in popup window scrollbar with border doesn't scroll

Problem:    Click in popup window scrollbar with border doesn't scroll.
Solution:   Correct column for the border. (Naruhiko Nishino, closes #4650)
diff --git a/src/version.c b/src/version.c
index 9d012bd..f274cef 100644
--- a/src/version.c
+++ b/src/version.c
@@ -778,6 +778,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1666,
+/**/
     1665,
 /**/
     1664,