Adding case flag to regexToString

[Bidek56]

Adding case flag to regexToString to address issue 82

[universalmind303]

lol, I was actually just about to open up a PR for this. I think we can push down most flags to rust (with a few exceptions).

export const regexToString = (r: string | RegExp): string => {
  if (isRegExp(r)) {
    if (r.flags.includes("g")) {
      throw new Error("global flag is not supported");
    }
    if (r.flags.includes("y")) {
      throw new Error("sticky flag is not supported");
    }
    return r.flags ? `(?${r.flags})${r.source}` : r.source;
  }

  return r;
};

[universalmind303]

#92

[universalmind303]

dropping in favor of #92