docs: def _forward_word(text, pos):
      """
      Move pos forward to the end of the next word. Words are composed of
      alphanumeric characters (letters and digits).
      """
      while pos < len(text) and not text[pos].isalnum():
          pos += 1
      while pos < len(text) and text[pos].isalnum():
          pos += 1
      return text, pos