[AriaNotify] Is NotificationId the right name?

[alisonmaher]

The current design of AriaNotify, as outlined in the spec PR and the explainer, includes a notificationId, which is a non-localized string that can be optionally used by an author to provide an AT with further context about the notification.

We have received feedback that the name notificationId is confusing, as the name implies identification rather than a way to tag common notifications across various web applications, and the name also implies that the ID would potentially need to be unique.

As such, the proposal is to update the name of notificationId to type as suggested in https://github.com/w3c/aria/discussions/1958#discussioncomment-6223785 to better describe what the property's true intention is.