patch 8.2.2321: Vim9: cannot nest closures

Problem:    Vim9: cannot nest closures.
Solution:   Add the nesting level to ISN_LOADOUTER and ISN_STOREOUTER.
            (closes #7150, closes #7635)

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2321,
 /**/
     2320,
 /**/