build/metalsmith/partials/collection-navigation.html
<nav id="collection-navigation">
{{collection-to-siblings}}
{{#each siblings}}
{{#if @first}}<h1>More in <em>{{../currentCollectionName}}</em></h1><ul>{{/if}}
{{#if this.layout}}
<li class="{{#is this.title ../title}}active{{/is}}">
<a
class="{{#contains @key ../collection}}active{{/contains}}"
href="{{../websiteRoot}}{{this.path.dir}}{{#if this.path.dir}}/{{/if}}{{this.path.base}}"
>{{this.title}}</a>
</li>
{{/if}}
{{#if @last}}</ul>{{/if}}
{{/each}}
</nav>