CC a11y: publish combobox checklist - draft content

[brunerae]

Follow-up from https://github.com/uswds/uswds/issues/5596

Checklist

A11Y

• [ ] Review checklist content
• [ ] Final approval of checklist content

Content

• [x] Draft checklist content and send for review with A11Y
• [ ] Final edits to checklist content

Dev

• [x] #2670

References

Critical Checklist spreadsheet List of all components

[finekatie]

I have finished drafting the gherkins and they are ready for review, @amycole501 and @alex-hull !