scope replaceKeywordBlock_dyn

sinterface #IReplacer {
  S[] get(LS tok, int iOpening, int iClosing);
}

static LS replaceKeywordBlock_dyn(S bracket default "{", LS tok, S keyword, IReplacer func) {
  for (int i = 0; i < 1000; i++) {
    int idx = findCodeTokens(tok, keyword, bracket);
    if (idx < 0)
      break;
    int j = findEndOfBracketPart(tok, idx+2);
    
    S[] be = func?.get(tok, idx+2, j-1);
    tok.set(idx, unnull(first(be)));
    tok.set(idx+1, " ");
    tok.set(idx+2, "");
    tok.set(j-1, unnull(second(be)));
    reTok(tok, idx, j);
  }
  ret tok;
}

end scope

Began life as a copy of #1018806