feat(series): add label before series' posts list

templates/series.html

@@ -20,6 +20,9 @@
     </section>
 
     <div id="posts-list">
+        <h2 class="bottom-divider">
+            {{ macros_translate::translate(key="all_posts", default="All posts", language_strings=language_strings) }}
+        </h2>
         {%- if paginator %}
             {%- set pages = paginator.pages -%}
         {% else %}