message: Allow to replace an element instead of append to body
diff: @@ -159,9 +159,14 @@ where
  let document = window.document().unwrap();
  let body = document.body().unwrap();
  - let _ = body
  + let _ = match body.query_selector("#iced_root").unwrap() {
  + Some(e) => body
  + .replace_child(&canvas, &e)
  + .expect("Could not replace iced_root"),
  + None => body
  .append_child(&canvas)
  - .expect("Append canvas to HTML body");
  + .expect("Append canvas to HTML body"),
  + };
  }
  let (compositor, renderer) = C::new(compositor_settings, Some(&window))?;
  