docs: function isKanaWithTrailingLatin(str) {
    REGEX_IS_KANA_WITH_TRAILING_LATIN = REGEX_IS_KANA_WITH_TRAILING_LATIN ||
      new RegExp('^' + '[' + R_KANA + ']+' + '[' + R_LATIN + ']' + '$');
    return REGEX_IS_KANA_WITH_TRAILING_LATIN.test(str);
  }