message: Duplicate comment about storage event iframe
diff: <html lang="en">
  <head>
  <meta charset="UTF-8">
  + <!--
  + Only other windows get notified when we change local storage, so
  + this is used in an invisible iframe to send a message to JS in
  + ../templates/rustdoc/body.html when local storage changes so we can
  + detect rustdoc changing the theme
  + -->
  <script type="text/javascript">
  onstorage = function(ev) {
  parent.postMessage({
  