patch 8.2.3974: Vim9: LISTAPPEND instruction does not check for a locked list

Problem:    Vim9: LISTAPPEND instruction does not check for a locked list.
Solution:   Check whether the list is locked. (closes #9452)
diff --git a/src/version.c b/src/version.c
index 1fc6dac..12e236c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -750,6 +750,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3974,
+/**/
     3973,
 /**/
     3972,