docs : fix tests urls on index

_posts/tests/2010-01-01-index.html

@@ -8,7 +8,7 @@ is_index_page: true
 <ul>
   {% for post in site.categories.tests reversed %}
     {% if post.is_index_page != true %}
-      <li><a href="{{ post.url }}">{{ post.title }}</a></li>
+      <li><a href="..{{ post.url }}">{{ post.title }}</a></li>
     {% endif %}
   {% endfor %}
 </ul>