message: Fix editing of <sub> & <sup> & <u>
diff: @@ -121,6 +121,12 @@ function parseElement(n: HTMLElement, partCreator: PartCreator, lastNode: HTMLEl
  return partCreator.plain(`\`${n.textContent}\``);
  case "DEL":
  return partCreator.plain(`<del>${n.textContent}</del>`);
  + case "SUB":
  + return partCreator.plain(`<sub>${n.textContent}</sub>`);
  + case "SUP":
  + return partCreator.plain(`<sup>${n.textContent}</sup>`);
  + case "U":
  + return partCreator.plain(`<u>${n.textContent}</u>`);
  case "LI": {
  const indent = " ".repeat(state.listDepth - 1);
  if (n.parentElement.nodeName === "OL") {
  