docs_contents.html

<div class="unit one-fifth hide-on-mobiles">
  <aside>
    {% for section in site.data.docs_nav %}
      <h4>{{ section.title }}</h4>
      <ul>
        {%- for item in section.docs -%}
          {%- assign item_page = site.docs | where: "url", item.link | first -%}
          {%- capture item_html -%}
            <a href="{{ item_page.url | relative_url }}">
              {{ item_page.menu_name | default: item_page.title }}
            </a>
          {% endcapture %}
          <li{% unless item_page.url != page.url %} class="current"{% endunless %}>{{ item_html }}</li>
        {% endfor %}
      </ul>
    {% endfor -%}
  </aside>
</div>