use tagList with full filter instead of just excluding posts

_includes/postslist.njk

@@ -4,7 +4,7 @@
     <a href="{{ post.url | url }}" class="postlist-link">{% if post.data.title %}{{ post.data.title }}{% else %}<code>{{ post.url }}</code>{% endif %}</a>
     <time class="postlist-date" datetime="{{ post.date | htmlDateString }}">{{ post.date | readableDate }}</time>
     {% for tag in post.data.tags %}
-      {%- if tag != "posts" -%}
+      {%- if collections.tagList.indexOf(tag) != -1 -%}
       {% set tagUrl %}/tags/{{ tag }}/{% endset %}
       <a href="{{ tagUrl | url }}" class="tag">{{ tag }}</a>
       {%- endif -%}