lang: ast: use fancy index manipulation to reduce the size of ast_node_type

lang/ast/unit-package.c

@@ -100,11 +100,11 @@ struct ast_node_type unit_package_node_ops = {
 	.n_state_size = sizeof(struct unit_package_parser_state),
 	.n_node_size = sizeof(struct ivy_ast_unit_package_node),
 	.n_symbol_parsers = {
-		[IVY_SYM_DOT] = parse_dot,
+		SYM_PARSER(DOT, parse_dot),
 	},
 	.n_token_parsers = {
-		[IVY_TOK_IDENT] = parse_ident,
-		[IVY_TOK_LINEFEED] = parse_linefeed,
+		TOK_PARSER(IDENT, parse_ident),
+		TOK_PARSER(LINEFEED, parse_linefeed),
 	}
 
-};
+};