// rtrims each item
static LS tok_splitAtEmptyLines(S s) {
  new L<Int> indices;
  LS tok = javaTokWithAllBrackets_cached(s);
  new LS out;
  int start = 0;
  S spacing = "";
  for (int i = 2; i+1 < l(tok); i += 2) {
    int idx = indexOf_regexp(tok.get(i), "\r?\n\\s*\r?\n");
    if (idx < 0) continue;
    int idx2 = idx+1;
    if (tok.get(i).charAt(idx) == '\r') ++idx2;
    out.add(dropPrefix("\n", spacing + joinSubList(tok, start, i)));
    start = i+1;
    spacing = substring(tok.get(i), idx2); // TODO: not exact
  }
  if (start < l(tok))
    out.add(dropPrefix("\n", spacing + joinSubList(tok, start)));
  ret out;
}