Fixed another localizeddate usage

Author: wouterj

app/Resources/views/blog/post_show.html.twig

@@ -32,7 +32,10 @@
         <div class="row post-comment">
             <h4 class="col-sm-3">
                 <strong>{{ comment.authorEmail }}</strong> {{ 'post.commented_on'|trans }}
-                <strong>{{ comment.publishedAt|localizeddate('medium', 'short') }}</strong>
+                {# it's not mandatory to set the timezone in localizeddate(). This is done to
+                   avoid errors when the 'intl' PHP extension is not available and the application
+                   is forced to use the limited "intl polyfill", which only supports UTC and GMT #}
+                <strong>{{ comment.publishedAt|localizeddate('medium', 'short', null, 'UTC') }}</strong>
             </h4>
             <div class="col-sm-9">
                 {{ comment.content|md2html }}