Tabs aria-selected is not supported on role link

**Describe the bug**

Tabs example suggests using semantics that's not supported and throws an accessibility error.

"aria-selected is not supported on role link"

We should investigate using different semantics when displaying tabs as links. Maybe we could use `aria-current="section"` instead?

**To Reproduce**

Steps to reproduce the behavior:

1. Go to https://vanillaframework.io/docs/patterns/tabs#navigation
2. Validate accessibility e.g. with axe devtools
3. See the error thrown

**Additional context**

https://www.stefanjudis.com/blog/aria-selected-and-when-to-use-it/#how-to-not(!)-use-%60aria-selected%60
https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Attributes/aria-selected
https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Attributes/aria-current

Start at the tabs navigation example at vanilla-framework.io/docs/patterns/tabs#navigation and reproduce the aria-selected error with axe DevTools. Read the linked ARIA guidance, compare aria-selected with aria-current="section", and confirm the updated example passes accessibility validation.

Written by the indexing model from the issue text.