* REFACTOR: Rename SiteSetting.disable_edit_notifications to disable_system_edit_notifications
- The older name could cause some confusion because the setting does not disable all edit notifications, only system ones.
* FIX: Add frozen_string_literal: true in the migration
* DEV: Deprecate 'disable_edit_notifications'
This reduces chances of errors where consumers of strings mutate inputs
and reduces memory usage of the app.
Test suite passes now, but there may be some stuff left, so we will run
a few sites on a branch prior to merging
* Add revision number to notification url
* Pop modal on route change
* Add semicolon
* Ensure modal pops even when navigating within a topic
* Ensure modal pops when visiting from other page
* Fix eslint errors
* Fix prettier errors
* Add callback for notification item click
* Remove stray revisionUrl function
* Rename to afterRouteComplete
Rails yanked out observers many many years ago, instead the functionality
was yanked out to a gem that is very lightly maintained.
For example: if we want to upgrade to rails 5 there is no published gem
Internally the usage of observers had quite a few problem.
The series of refactors renamed a bunch of classes to give us more clarity
and removed some magic.
