fix: multiple modifiers on a class

Author: gbprod

grammar.js

@@ -284,7 +284,8 @@ module.exports = grammar({
 
     class_declaration: $ => prec.right(seq(
       optional(field('attributes', $.attribute_list)),
-      optional(field('modifier', choice($.final_modifier, $.abstract_modifier, $.readonly_modifier))),
+      optional(field('modifier', choice($.final_modifier, $.abstract_modifier))),
+      optional(field('modifier', $.readonly_modifier)),
       keyword('class'),
       field('name', $.name),
       optional($.base_clause),

src/grammar.json

@@ -1220,10 +1220,6 @@
                     {
                       "type": "SYMBOL",
                       "name": "abstract_modifier"
-                    },
-                    {
-                      "type": "SYMBOL",
-                      "name": "readonly_modifier"
                     }
                   ]
                 }
@@ -1233,6 +1229,22 @@
               }
             ]
           },
+          {
+            "type": "CHOICE",
+            "members": [
+              {
+                "type": "FIELD",
+                "name": "modifier",
+                "content": {
+                  "type": "SYMBOL",
+                  "name": "readonly_modifier"
+                }
+              },
+              {
+                "type": "BLANK"
+              }
+            ]
+          },
           {
             "type": "ALIAS",
             "content": {

src/node-types.json

@@ -1350,7 +1350,7 @@
         ]
       },
       "modifier": {
-        "multiple": false,
+        "multiple": true,
         "required": false,
         "types": [
           {