fixed back location on edit guidance page

Author: Jon Roobottom

app/views/site/cancel-availability/edit-guidance.html

@@ -4,7 +4,7 @@
 
 {% block beforeContent %}
 {{ backLink({
-  href: '/site/' + site_id + '/cancel-availability/cancel-or-edit'
+  href: '/site/' + site_id + '/availability/day'
 }) }}
 {% endblock %}