Add alt option to Spinner

[owenniblock]

I'll fill this out when it's ready for review 🙂

Closes https://github.com/github/accessibility/issues/6108

Changelog

New

Changed

Removed

Rollout strategy

• [ ] Patch release
• [ ] Minor release
• [ ] Major release; if selected, include a written rollout or migration plan
• [ ] None; if selected, include a brief description as to why

Testing & Reviewing

Merge checklist

• [ ] Added/updated tests
• [ ] Added/updated documentation
• [ ] Added/updated previews (Storybook)
• [ ] Changes are SSR compatible
• [ ] Tested in Chrome
• [ ] Tested in Firefox
• [ ] Tested in Safari
• [ ] Tested in Edge
• [ ] (GitHub staff only) Integration tests pass at github/github (Learn more about how to run integration tests)

[changeset-bot[bot]]

⚠️ No Changeset found

Latest commit: 55baf104459323cd0d9b1dee2ef1d822ded3b4c0

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[github-actions[bot]]

size-limit report 📦

Path	Size
packages/react/dist/browser.esm.js	88.57 KB (+0.1% 🔺)
packages/react/dist/browser.umd.js	88.74 KB (-0.12% 🔽)