refactor: rename _partials to _includes

source/_includes/post/old-post-message.html.twig

@@ -0,0 +1,15 @@
+{% macro shouldDisplayOldPostMessage(post) %}
+    {% set cutOffDate = 'today -1 year'|date('U') %}
+
+    {% if post.date is not empty %}
+        {{ post.date <= cutOffDate }}
+    {% endif %}
+{% endmacro %}
+
+{% import _self as helpers %}
+
+{% if helpers.shouldDisplayOldPostMessage(post)|trim %}
+      <div class="p-6 my-10 border border-gray-300 dark:bg-gray-800 dark:border-gray-700">
+          <p><strong>Warning:</strong> This post is over a year old. I don't always update old posts with new information, so some of this information may be out of date.</p>
+      </div>
+{% endif %}