docs: script update to account for double-nested list items when scrolling sidenav into view

  if (navObj.is(':visible')) {

    var selected = $(".selected", navObj);

    if (selected.length == 0) return;

    if (selected.is("div")) selected = selected.parent();

    if (selected.is("div")) selected = selected.parent(); // when the selected item is a parent

    var scrolling = document.getElementById(nav);

    var navHeight = navObj.height();

    var offsetTop = selected.position().top;

    if (selected.parent().parent().is(".toggle-list")) offsetTop += selected.parent().parent().position().top;

    if(offsetTop > navHeight - 92) {

      scrolling.scrollTop = offsetTop - navHeight + 92;

    // handle nested items

    if (selected.parent().parent().is(".toggle-list")) {

      selected = selected.parent().parent();

      // handle second level nested items

      if (selected.parent().parent().is(".toggle-list")) {

        selected = selected.parent().parent();

      }

      offsetTop += selected.position().top;

    }

    // 180px from the bottom of the list is the threshold

    if(offsetTop > navHeight - 180) {

      scrolling.scrollTop = offsetTop - navHeight + 180;

    }

  }

}