update twig to 2.9

templates/notbanned.html

@@ -1,7 +1,7 @@
-{% filter remove_whitespace %}
+{% apply spaceless %}
 {# Automatically removes unnecessary whitespace #}
 <div class="ban">
   <h2>You are not banned!</h2>
   <p class="reason">Well done on not being terrible!</p>
 </div>
-{% endfilter %}
+{% endapply %}