docs: private void appendRubyElements(RendersnakeHtmlCanvas html,
  			List<SubtitleItem.Inner> elements) throws IOException {
  		for (SubtitleItem.Inner element : elements) {
  			String kanji = element.getKanji();
  			if (kanji != null) {
  				html.ruby();
  				html.spanKanji(kanji);
  				html.rt(element.getText());
  				html._ruby();
  			} else {
  				html.write(element.getText());
  			}
  		}
  	}