patch 8.2.3981: Vim9: debugging a for loop doesn't stop before it starts

Problem:    Vim9: debugging a for loop doesn't stop before it starts.
Solution:   Keep the DEBUG instruction before the expression is evaluated.
            (closes #9456)
diff --git a/src/version.c b/src/version.c
index 2ca87fe..521fe39 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3981,
+/**/
     3980,
 /**/
     3979,