code: private static void addPluralRules(TypeSpec.Builder type) {
      FieldSpec field = FieldSpec.builder(PLURAL_RULES, "pluralRules", PRIVATE, STATIC, FINAL)
          .initializer("new $T()", PLURAL_RULES)
          .build();
      
      MethodSpec method = MethodSpec.methodBuilder("getPluralRules")
          .addModifiers(PUBLIC)
          .returns(PLURAL_RULES)
          .addStatement("return pluralRules")
          .build();
  
      type.addField(field);
      type.addMethod(method);
    }
docs: Add static instance of plural rules and accessor method.