patch 8.2.4231: Vim9: map() gives type error when type was not declared

Problem:    Vim9: map() gives type error when type was not declared.
Solution:   Only check the type when it was declared, like extend() does.
            (closes #9635)
diff --git a/src/version.c b/src/version.c
index cbc938a..7341fcc 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4231,
+/**/
     4230,
 /**/
     4229,