patch 8.2.2481: Vim9: confusing error when variable arguments have default

Problem:    Vim9: confusing error when variable arguments have a default
            value.
Solution:   Give a specific error message. (closes #7793)
diff --git a/src/version.c b/src/version.c
index 871e048..c6f44a4 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2481,
+/**/
     2480,
 /**/
     2479,