code: public Content getFieldsContentHeader(boolean isLastContent) {
          HtmlTree li = new HtmlTree(HtmlTag.LI);
          if (isLastContent)
              li.addStyle(HtmlStyle.blockListLast);
          else
              li.addStyle(HtmlStyle.blockList);
          return li;
      }
docs: Return the header for serializable fields content section.
  
  @param isLastContent true if the cotent being documented is the last content.
  @return a content tree for the header