Add striptags filter to description meta header

Thanks @PontusHorn

themes/default/index.twig

@@ -5,7 +5,7 @@
 
     <title>{% if meta.title %}{{ meta.title }} | {% endif %}{{ site_title }}</title>
     {% if meta.description %}
-        <meta name="description" content="{{ meta.description }}">
+        <meta name="description" content="{{ meta.description|striptags }}">
     {% endif %}{% if meta.robots %}
         <meta name="robots" content="{{ meta.robots }}">
     {% endif %}