class Jekyll::Drops::SiteDrop

def related_posts

We should remove this in 4.0 and switch to `{{ post.related_posts }}`.
recent posts.
them, either through LSI if it's enabled, or through the most
`{{ site.related_posts }}` is how posts can get posts related to 
def related_posts
  return nil unless @current_document.is_a?(Jekyll::Document)
  @current_document.related_posts
end