static S html_addLinkToSpan(S html, S id, S link) {
  L<S> tok = htmlTok(html);
  for (L<S> tag : findContainerTagWithParams(tok, "span", +id)) {
    tag = subList(tag, 2, l(tag)-2);
    replaceTokens(tag, ahref(link, join(tag)));
  }
  ret join(tok);
}