aXe violation for <audio> element without caption should be a "need inspection"

[Wildebrew]

aXe flags an <audio> element without an associated <track> element as a violation.
This is not always the case.

An <audio> element requires a text transcript, not synchronized captions.
That transcript can be provided in a myriad of ways other than using the <track> element, e.g. by displaying it in HTML on the same page or even as a download link adjacent to the <audio> element.

There are also situations where the <audio> element itself does not need a transcript at all such as when it is used as an accessible aalternative to a visual cue.

We use an <audio> element to play a popping sound as an incoming chat message notification for a screen reader user. That does not need a caption.

I propose to revise this requirement to "needs verification".

[WilcoFiers]

Hey Birkir. We've been working on rules in Auto-WCAG to update the media rules. We'll likely update the rules with however that shakes out. My guess is it'll mean media rules will no longer return failures. We'll keep you posted!