Adds feature: Ajax Close/Open updates discussion automatically

Triggers jQuery event
Fixes #5544

app/assets/javascripts/issue.js.coffee

@@ -50,6 +50,7 @@ class @Issue
           new Flash(issueFailMessage, 'alert')
         success: (data, textStatus, jqXHR) ->
           if data.saved
+            $(document).trigger('issuable:change');
             if isClose
               $('a.btn-close').addClass('hidden')
               $('a.btn-reopen').removeClass('hidden')

app/assets/javascripts/notes.js.coffee

@@ -64,6 +64,8 @@ class @Notes
     # fetch notes when tab becomes visible
     $(document).on "visibilitychange", @visibilityChange
 
+    $(document).on "issuable:change", @refresh
+
   cleanBinding: ->
     $(document).off "ajax:success", ".js-main-target-form"
     $(document).off "ajax:success", ".js-discussion-note-form"