message: Avoid error in `comments-time-machine-links`
  It appeared in reviews like
diff: @@ -51,8 +51,9 @@ function addDropdownLink(comment: HTMLElement, timestamp: string): void {
  }
  function init(): void {
  + // PR reviews' main content has nested `.timeline-comment`, but the deepest one doesn't have `relative-time`. These are filtered out with `:not([id^="pullrequestreview"])`
  const comments = select.all(`
  - :not(.js-new-comment-form) > .timeline-comment:not(.rgh-time-machine-links),
  + :not(.js-new-comment-form):not([id^="pullrequestreview"]) > .timeline-comment:not(.rgh-time-machine-links),
  .review-comment:not(.rgh-time-machine-links)
  `);
  