patch 8.2.0120: virtcol() does not check arguments to be valid

Problem:    virtcol() does not check arguments to be valid, which may lead to
            a crash.
Solution:   Check the column to be valid.  Do not decrement MAXCOL.
            (closes #5480)
diff --git a/src/version.c b/src/version.c
index 44bfd6b..e20bf5d 100644
--- a/src/version.c
+++ b/src/version.c
@@ -743,6 +743,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    120,
+/**/
     119,
 /**/
     118,