update twig to 2.9

templates/post_thread_fileboard.html

@@ -1,4 +1,4 @@
-{% filter remove_whitespace %}
+{% apply spaceless %}
 {# tabs and new lines will be ignored #}
 
 {# we are intentionally breaking the thread_ID convention: the jses need to handle this case differently #}
@@ -39,4 +39,4 @@
     <a href="{{ post.root }}{{ board.dir }}{{ config.dir.res }}{{ link_for(post) }}">[{% trans %}Reply{% endtrans %}]</a>
 
 </tr>
-{% endfilter %}
+{% endapply %}