another comment fix

git-svn-id: svn://svn.savannah.gnu.org/nano/trunk/nano@3389 35c25a1d-7b9e-4130-9fde-d3aeb78583b8

src/winio.c

@@ -3234,4 +3234,4 @@ void do_credits(void)
 
     total_refresh();
 }
-#endif
+#endif /* NANO_EXTRA */