Autocomplete: Announce autocomplete correctly in all ATs. Fixes #9631. 

Autocomplete: default functionality does not announce the suggestions correctly

I know that this pull request s not complete but wanted to open this so we could discuss an issue I have encountered during implementation.

I saw the example with categories and modified the implementation to announce the category correctly.

In trying to implement the unit tests for this, could not find an existing unit test. I also could not find any documentation on the "items" option (for the Menu widget) that is being used in the categories example. I also could not find evidence that this is standard functionality.

We have three options:
1. I could leave the implementation as is thereby formalizing the categories further as a "feature" and add a unit test for this,
2. I could implement a callback option for obtaining the full accessible name of an item, or
3. I could do both

Thoughts @scottgonzalez