blog/_src/_includes/related_posts.html

<aside class="related-posts">
    
    <h1 class="related-title">Related</h1>

    <div class="row">
        
        {% for post in site.posts limit:6 %}
    
            <article class="related-post col2">
                <a href="{{ post.url }}">
                    <h1 class="post-title">{{ post.title }}</h1>
                </a>
            </article>
    
        {% endfor %}

    </div>
    
</aside>