patch 8.2.3896: Vim9: no test for nested function not available later

Problem:    Vim9: no test for nested function not available later.
Solution:   Add a test.
diff --git a/src/version.c b/src/version.c
index 80d92fc..a09a0bf 100644
--- a/src/version.c
+++ b/src/version.c
@@ -750,6 +750,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3896,
+/**/
     3895,
 /**/
     3894,