Add paragraph tag around post excerpt

Wrap post excerpt in a paragraph tag for better formatting.

Author: codescape

_includes/article.html

@@ -32,7 +32,7 @@
   {% if is_single %}
     {{ content }}
   {% else %}
-    {{ post.excerpt }} <a href="{{ post.url }}">...weiterlesen</a>
+    <p>{{ post.excerpt | strip_html }} <a href="{{ post.url }}">...weiterlesen</a></p>p>
   {% endif %}
 
   {% if is_single and site.disqus_username %}