// tok must come from htmlTok
// returns content of all container tags found as CNC
// should be OK for both HTML and XML
static LL<S> contentsOfContainerTags(L<S> tok, S tag) {
  ret map contentsOfContainerTag(findContainerTag(tok, tag));
}

static LL<S> contentsOfContainerTags(S html, S tag) {
  ret contentsOfContainerTags(htmlTok(html), tag);
}