Add parameter for custom page title

src/_includes/main/content.njk

@@ -3,7 +3,7 @@ layout: main/base
 ---
 
 <header class="main__header">
-    <h1>{{ title }}</h1>
+    <h1>{{ pageTitle or title }}</h1>
     {% if intro %}
         <p>{{ intro }}</p>
     {% endif %}