static expandFormat(fmt, localeOpts = {}) {
    const expanded = expandMacroTokens(Formatter.parseFormat(fmt), Locale.fromObject(localeOpts));
    return expanded.map((t) => t.val).join("");
  }
Produce the the fully expanded format token for the locale
Does NOT quote characters, so quoted tokens will not round trip correctly
@param fmt
@param localeOpts
@returns {string}