accessibility(Autocomplete) implemented tab index and aria expanded

[gselderslaghs]

Proposed changes

Implemented tab index and aria expanded as described in #538

Todo:

• autocomplete functionality does not seem to be backward compatible with firefox < 113 and other older browsers (needs review) -> reviewed: won't fix for now, follow up in ticket and create new pull request when solution is found

Types of changes

• Bug fix (non-breaking change which fixes an issue).
• New feature (non-breaking change which adds functionality).
• Breaking change (fix or feature that would cause existing functionality to change).

Checklist:

• I have read the CONTRIBUTING document.
• My commit messages follows the conventional commit format
• My change requires a change to the documentation, and updated it accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.