ContainerImage.Pinniped/site/themes/pinniped/layouts/partials/docs-sidebar.html

<div class="side-nav">
    <ul>
        {{ $currentPage := . }}
        {{ range .Site.Menus.docs }}
            <li><a href="{{ .URL }}" {{ if (eq $currentPage.RelPermalink .URL)  }}class="active"{{ end }}>{{ .Name }}</a></li>
        {{ end }}
    </ul>
</div>