Fix Zen Mode not closing with ESC key

Closes #1025

CHANGELOG

 Please view this file on the master branch, on stable branches it's out of date.
 
 v 7.12.0 (unreleased)
+  - Fix Zen Mode not closing with ESC key (Stan Hu)
   - Add web hook support for note events (Stan Hu)
   - Disable "New Issue" and "New Merge Request" buttons when features are disabled in project settings (Stan Hu)
   - Allow to configure location of the `.gitlab_shell_secret` file. (Jakub Jirutka)

app/assets/javascripts/zen_mode.js.coffee

@@ -12,11 +12,11 @@ class @ZenMode
 
     $('body').on 'click', '.zen-enter-link', (e) =>
       e.preventDefault()
-      $(e.currentTarget).closest('.zennable').find('.zen-toggle-comment').prop('checked', true)
+      $(e.currentTarget).closest('.zennable').find('.zen-toggle-comment').prop('checked', true).change()
 
     $('body').on 'click', '.zen-leave-link', (e) =>
       e.preventDefault()
-      $(e.currentTarget).closest('.zennable').find('.zen-toggle-comment').prop('checked', false)
+      $(e.currentTarget).closest('.zennable').find('.zen-toggle-comment').prop('checked', false).change()
 
     $('body').on 'change', '.zen-toggle-comment', (e) =>
       checkbox = e.currentTarget