Added aria-owns link between input and dropdown list

[beattyml1]

Added aria-owns link between input and dropdown list, had to add unique ID generator and a switch v-if to v-show to make that really work.

[sagalbot]

Ahhh.. this is challenging. v-show was originally used, but swapped for v-if after it became apparent that v-show causes significant performance issues when rending multiple selects on a given page, especially if each one has hundreds or thousands of options to search through. v-show results in many extra dom nodes that impact performance.

I suppose aria-owns is invalid if the ID it's referencing doesn't exist?

[beattyml1]

I assumed it was but as I think about it I feel like if it's not there while the screen reader may not feel existentially happy it also probably isn't going to cause any bugs. My guess is technically invalid but all screen readers would still do their thing which to me is what we really care about. I'll switch it back to v-if and recheck the screen reader.

[sagalbot]

Awesome, thanks so much @beattyml1!

[beattyml1]

A quick update I've determined that v-shows definitely doesn't work quite as well as v-if and have tried to find a work around. I also tried doing some further screen reader testing and covered another screen reader issue that I was planning to resolve at the same time and update the PR when I get a chance.