code: public String rfc5988String() {
          StringBuilder builder = new StringBuilder();
          builder.append("<")
                  .append(href)
                  .append(">; rel=\"")
                  .append(rel)
                  .append("\"");
          return builder.toString();
      }
docs: Return the link in the format of RFC 5988 Web Linking.
  
  See <a href="http://tools.ietf.org/html/rfc5988#page-7">RFC 5988 Web Linking</a>
  
  @return String that contains the link with href and rel