Update Firefox notes for Notification.requestPermission() (#15929)
Update Firefox notes for Notification.requestPermission() (#15929)

* Copy notes for Firefox for Notification.requestPermission()

* Fix capitalization of note
chrisdavidmills/browser-compat-data,mdn/browser-compat-data,chrisdavidmills/browser-compat-data,mdn/browser-compat-data