Use .twig instead of .html.twig

source/_layouts/talk.html.twig

@@ -1,25 +0,0 @@
-{% extends "default.html.twig" %}
-
-{% block body_classes 'page--talks page--talks__talk' %}
-
-{% block content_wrapper %}
-    <main class="col-md-10">
-        <h1>{{ page.title }}</h1>
-
-        <p>At {{ page.location }} on {{ page.date|date(site.default_date_format) }}.</p>
-
-        {{ page.blocks.content|raw }}
-
-        {% if page.joindin %}
-            <p>
-                <a href="{{ page.joindin }}" class="btn btn-primary">Rate this talk</a>
-            </p>
-        {% endif %}
-
-        {% if page.slides_embed %}
-            <div class="slides">
-                {{ page.slides_embed|raw }}
-            </div>
-        {% endif %}
-    </main>
-{% endblock content_wrapper %}