title: Searching for page in site.pages by path without iteration
body: <p>I have a path to some page from root in Jekyll as a variable <code>path</code>.  I want to get some variables from FrontMatter of that page. How could I find this page in <code>site.pages</code> without iterating over all pages?
  I mean something like</p>
  <pre><code>{% assign aim = site.pages[path] %}
  </code></pre>
  <p>instead of</p>
  <pre><code>{% for p in site.pages %}
    {% if p.path == path %}
      {% assign aim = p %}
    {% endif %}
  {% endfor %}
  </code></pre>
  <p>Will this solution be faster for a site with a thousand of pages?</p>