code: public Content getNavLinkNext() {
          Content li;
          if (next != null) {
              Content nextLink = getLink(new LinkInfoImpl(configuration,
                      LinkInfoImpl.Kind.CLASS, next)
                      .label(nextclassLabel).strong(true));
              li = HtmlTree.LI(nextLink);
          }
          else
              li = HtmlTree.LI(nextclassLabel);
          return li;
      }
docs: Get link to next class.
  
  @return a content tree for the next class link