message: Show tooltip for skippable hints
diff: @@ -88,6 +88,7 @@ function loadHint (hint: ChallengeHint): HTMLElement {
  elem.style.fontFamily = 'Roboto,Helvetica Neue,sans-serif'
  if (!hint.unskippable) {
  elem.style.cursor = 'pointer'
  + elem.title = 'Double-click to skip'
  }
  elem.style.fontSize = '14px'
  elem.style.display = 'flex'
  