site/_includes/sidebar.html

{% unless page.no_sidebar %}
<aside class="sidebar">
  {% assign doc_version = page.url | replace:'/',' ' | truncatewords: 2 | remove:'...' | replace:'docs','' | lstrip %}
  <a class="button is-info">
    Version: {{ doc_version }}
  </a>
  <hr />
  {% for group in site.data.sidebar.groups %}{% assign docs = group.docs %}
  <p>
    {{ group.name }}
  </p>
  <ul class="sidebar-items">
    {% for doc in docs %}
    {% capture doc_url %}../../{{ group.dir }}/{{ doc.endpoint }}/{% endcapture %}
    <li{% if doc_url == page.url %} class="active"{% endif %}>
      <a href="../../{{ group.dir }}/{{ doc.endpoint }}">
      {{ doc.name }}
      </a>
    </li>
    {% endfor %}
  </ul>
  {% endfor %}
</aside>
{% endunless %}