Clarify how aria-* attributes are expected to trickle down to nested elements

[scottaohara]

when discussing #1972

i raised the question as to whether the readonly status would trickle down to the gridcell alone, or if it would also impact the readonly state of any form controls that were nested within the gridcell if it were to be allowed on rows, per 1972.

But this raised the question of whether that would also be true if it was declared on the gridcell specifically that then had nested form control(s).

This then opened a larger conversation about other attributes (aria-disabled, aria-required) and how those properties should be inherited (or not) into nested elements that support those properties, but maybe shouldn't be auto-inheriting those properties?

I'm going to leave this issue rather sparse to start, i'm sure more discussion can help figure out how this moves forward and if each attribute needs to be considered separately, or if there's one unified agreement on how to allow properties to inherit, or not.

[scottaohara]

according to #1632, we had discussed about removing aria-disabled from being supported on role=group - which unless anyone wants to revise their thoughts on that, seems like it could help at least partially answer this issue - e.g., 'no. aria-* should not propagate to descendant elements unless specifically specified to do so"

[spectranaut]

Minutes from today's meeting: https://www.w3.org/2023/10/12-aria-minutes.html#t06

[pkra]

Cross linking #1130 (comment)