Sortable Table Header cells are not accessible via keyboard or read as clickable by screen reader

[chawes13]

The child of the th should likely be a button to get most of this functionality for free.

The th should also have the correct aria-sort property.

Example: https://dequeuniversity.com/library/aria/table-sortable

Raised by @kweingart08

[aalejandromr]

@chawes13 A couple of questions:

• Should this also follow the inspiration of the arrow up/down content moved to the button instead?
• Should it also follow the inspiration of 100% width on the button?
• I do feel like the linked inspiration showcases a good practice on what the caption should have (columns + active sorted column callout). It is computed tho. Any thoughts of following that pattern? If so, it would change the current purpose of the caption prop. We would possibly need a migration guide callout there as well.

@marchwiany I would love to hear your thoughts here