[Accessibility Docs] Table of contents

Using [this template](https://docs.google.com/document/d/1IwFMfJrTfJPXDcVJfLWXYkw-pjgWhBWo4GX8X098Q64/edit#), create accessibility docs for [Table of contents](https://vanillframework.io/docs/patterns/table-of-contents)

Start with the linked accessibility documentation template and the Table of contents page in the Vanilla Framework documentation. Create the accessibility docs for that pattern using the template, and consider the work done when the new documentation follows the template and covers the linked component.

Written by the indexing model from the issue text.