docs: private static URI normalizeHrefValue(final URI fileName, final String tail, final String topicId) {
          //Insert first topic id only when topicid is not set in keydef
          //and keyref has elementid
          if (fileName.getFragment() == null && !"".equals(tail)) {
              return setFragment(fileName, topicId + tail);
          }
          return toURI(fileName + tail);
      }