NavList: Add aria-current to active nav item

[camertron]

What are you trying to accomplish?

This PR updates NavList so that the currently active nav item has an aria-current attribute set on it.

Integration

No changes necessary in production.

List the issues that this change affects.

Fixes https://github.com/github/primer/issues/2313

Risk Assessment

• Low risk the change is small, highly observable, and easily rolled back.
• Medium risk changes that are isolated, reduced in scope or could impact few users. The change will not impact library availability.
• High risk changes are those that could impact customers and SLOs, low or no test coverage, low observability, or slow to rollback.

Accessibility

• No new axe scan violation - This change does not introduce any new axe scan violations.

Merge checklist

• Added/updated tests
  - [ ] Added/updated documentation
  - [ ] Added/updated previews (Lookbook)
  - [ ] Tested in Chrome
  - [ ] Tested in Firefox
  - [ ] Tested in Safari
  - [ ] Tested in Edge

Take a look at the What we look for in reviews section of the contributing guidelines for more information on how we review PRs.

[changeset-bot]

🦋 Changeset detected

Latest commit: 9579cc0

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@primer/view-components	Patch

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[jamieshark]

@camertron - I had originally brought this up in the #primer-rails channel because of https://github.com/github/accessibility-audits/issues/3650. That issue suggests a solution of not just aria-current="true" but aria-current="page". Do we know if the value of the attribute will make a difference to the user? Maybe @primer/accessibility-reviewers might have more context.

[camertron]

Woops! Good catch @jamieshark, I will fix that asap. Based on these docs, page looks much more correct than true, so I don't think we need to involve @primer/accessibility-reviewers.