feat(RAC): Expose useRenderProps hook

[sebald]

Hey, here's a simple addition to the RAC API: by exposing useRenderProps, RAC users can build their own components that integrate more seamlessly with other RAC components.

✅ 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:

[snowystinger]

Preliminary approval, will bring up with the team. Thanks for the PR.

Some of this work will also be done when we redo our docs site with a focus on how to creating more custom components that fit naturally in with RAC.

[devongovett]

Seems ok. I guess the only question we had was whether including data-rac as we currently do would be unexpected for third party components.

[snowystinger]

merged, if we decide to change the data-rac we can follow that up