Escape HTML code in pre blocks

Author: alerque

templates/page.html

@@ -29,7 +29,7 @@ <h3 class="title is-3">{{ typesetter }}</h3>
     </p>
 
     <h4 class="title is-4">Input document</h4>
-    {% set source = load_data(path=manifest.src) %}
+    {% set source = load_data(path=manifest.src) | safe %}
     <pre>{{ source }}</pre>
 
     <h4 class="title is-4">Render command</h4>