update Notifications API content to better explain persistent events and not persistent events

[skyclouds2001]

MDN URL

https://developer.mozilla.org/en-US/docs/Web/API/Notifications_API

What specific section or headline is this issue about?

No response

What information was incorrect, unhelpful, or incomplete?

see #30717 (review)
reference to https://notifications.spec.whatwg.org/

Our documentation for the Notifications API has a big flaw: we don't explain the difference between persistent events and not persistent events.

This may be done in a follow-up PR, and we would need to update:

• the overview page (Notifications API) to explain these two concepts.
• Rework _Using the notifications API", maybe dividing it into two guides, one for persistent notifications (associated with service workers, and one for non-persistent notifications.

What did you expect to see?

ditto.

Do you have any supporting links, references, or citations?

No response

Do you have anything more you want to share?

No response

MDN metadata

No response