docs: fix RSP ListBox Loading example

[yihuiliao]

Closes

✅ 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:

Confirm that Listbox Loading example is rendering

Before: https://react-spectrum.adobe.com/react-spectrum/ListBox.html#loading After: https://reactspectrum.blob.core.windows.net/reactspectrum/046664d6df70ea1aed0fec36076bd113810470c0/docs/react-spectrum/ListBox.html#loading

(not sure why it didn't comment but you can double check the commit hash to make sure it's the correct one)

🧢 Your Project:

[rspbot]

Build successful! 🎉

• View the storybook
• View the storybook-19
• View the storybook-17
• View the storybook-16
• View the documentation

[rspbot]

## API Changes unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any', access: 'private' } unknown top level export { type: 'any', access: 'private' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'identifier', name: 'Column' } unknown top level export { type: 'identifier', name: 'Column' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown type { type: 'link' } unknown type { type: 'link' } unknown type { type: 'link' } unknown type { type: 'link' } unknown type { type: 'link' } unknown type { type: 'link' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' } unknown top level export { type: 'any' }