Enable Twig debug doesn't work?
Try to change your development.services.yml to following. this  works for me correctly(I hope works for you too) .  

services:
  cache.backend.null:
    class: Drupal\Core\Cache\NullBackendFactory

# Enable Twig debugging.
parameters:
 twig.config:
   debug: true
   auto_reload: true
   cache: false


also  this article about setting up debugging on Drupal 8 is very good for future visitors of this question.