docs: update s2 examples to fix type error

[yihuiliao]

Noticed that the examples in the docs weren't quite working while figuring out the demo for the intern presentation. It does work without adding the as const locally but the type error can be confusing

✅ Pull Request Checklist:

• Included link to corresponding React Spectrum GitHub Issue.
• Added/updated unit tests and storybook for this change (for new code or code which already has tests).
• Filled out test instructions.
• Updated documentation (if it already exists for this component).
• Looked at the Accessibility Practices for this feature - Aria Practices

📝 Test Instructions:

🧢 Your Project:

[rspbot]

Build successful! 🎉

• View the storybook
• View the S2 storybook
• View the documentation

[devongovett]

hopefully people know this is typescript and not javascript :D