code: @Override
      public void addComment(XmlElement xmlElement) {
          xmlElement.addElement(new TextElement("<!--"));
          StringBuilder sb = new StringBuilder();
          sb.append("  WARNING - ");
          sb.append(MergeConstants.NEW_ELEMENT_TAG);
          xmlElement.addElement(new TextElement(sb.toString()));
          xmlElement.addElement(new TextElement("-->"));
      }
docs: xml中的注释
  
  @param xmlElement