patch 8.2.0492: Vim9: some error messages not tested

Problem:    Vim9: some error messages not tested.
Solution:   Add more tests.  Remove dead code.  Fix uncovered bugs.
diff --git a/src/version.c b/src/version.c
index 31f2f74..5fc599c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -739,6 +739,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    492,
+/**/
     491,
 /**/
     490,