patch 8.2.2194: Vim9: cannot use :const or :final at the script level

Problem:    Vim9: cannot use :const or :final at the script level.
Solution:   Support using :const and :final. (closes #7526)
diff --git a/src/vim.h b/src/vim.h
index ebd7db4..1dedd81 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -2144,7 +2144,7 @@
 // Flags for assignment functions.
 #define ASSIGN_FINAL	1   // ":final"
 #define ASSIGN_CONST	2   // ":const"
-#define ASSIGN_NO_DECL	4   // "name = expr" without ":let" or ":const"
+#define ASSIGN_NO_DECL	4   // "name = expr" without ":let"/":const"/":final"
 
 #include "ex_cmds.h"	    // Ex command defines
 #include "spell.h"	    // spell checking stuff