code: protected Content getNavShowLists(DocPath link) {
          DocLink dl = new DocLink(link, path.getPath(), null);
          Content framesContent = getHyperLink(dl, framesLabel, "", "_top");
          Content li = HtmlTree.LI(framesContent);
          return li;
      }
docs: Get "FRAMES" link, to switch to the frame version of the output.
  
  @param link File to be linked, "index.html"
  @return a content tree for the link