code: private static boolean serialDocInclude(Utils utils, Element element) {
          if (utils.isEnum(element)) {
              return false;
          }
          List<? extends DocTree> serial = utils.getSerialTrees(element);
          if (!serial.isEmpty()) {
              CommentHelper ch = utils.getCommentHelper(element);
              String serialtext = Utils.toLowerCase(ch.getText(serial.get(0)));
              if (serialtext.contains("exclude")) {
                  return false;
              } else if (serialtext.contains("include")) {
                  return true;
              }
          }
          return true;
      }
docs: Return true if the given Element should be included
  in the serialized form.
  
  @param element the Element to check for serializability.