void AddKeywordItems(GenericMenu gm)
 {
     gm.AddItem(new GUIContent($"Keyword/Boolean"), false, () => AddInputRow(new ShaderKeyword(KeywordType.Boolean), true));
     gm.AddItem(new GUIContent($"Keyword/Enum"), false, () => AddInputRow(new ShaderKeyword(KeywordType.Enum), true));
     gm.AddSeparator($"Keyword/");
     foreach (var builtinKeywordDescriptor in KeywordUtil.GetBuiltinKeywordDescriptors())
     {
         var keyword = ShaderKeyword.Create(builtinKeywordDescriptor);
         AddBuiltinKeyword(gm, keyword);
     }
 }