AX mapping for aria-details

[pkra]

From w3c/aria#1009

What is more concerning is there is no mapping for aria-details for AX API, which means using this property will be useless to users of macOS.

That's still the case in the spec but iiuc (cf w3c/aria#1009 (comment)) aria-details is now supported.

[scottaohara]

per work going on in w3c/html-aam#359, this should be using AXDetailsElements, I believe the following would be how it would be noted in the spec:

e.g.,

AXDetailsElements points to accessible nodes matching IDREFs, if the referenced objects are in the accessibility tree

If I'm correct on this, i can make the PR