code: protected void addPackageUse(Content contentTree) throws IOException {
          HtmlTree ul = new HtmlTree(HtmlTag.UL);
          ul.addStyle(HtmlStyle.blockList);
          if (configuration.packages.length > 1) {
              addPackageList(ul);
          }
          addClassList(ul);
          contentTree.addContent(ul);
      }
docs: Add the package use information.
  
  @param contentTree the content tree to which the package use information will be added