ARIA in HTML updates re: popovertarget and command attributes

[scottaohara]

ARIA in HTML is updating to identify misuse of aria-expanded when used on a button element that also have a popovertarget or command attribute specified.

These updates mirror other similar rules such as input type=checkbox discouraging use of aria-checked since the browser already handles these states and the use of author specified ARIA attributes is redundant at best, and can lead to potential misalignments that browsers should correct for - though there have been issues with this in the past.

This reduced test case helps illustrate the updates to the spec.

[gezlemon]

Thanks, @scottaohara I've added checks for aria-expanded being used when there is also have a popovertarget or command attribute present.

[scottaohara]

thank you @gezlemon !