Add startViewTransition support

[brophdawg11]

This PR adds initial support for document.startViewTransition behind some unstable_ APIs so we can get it out into folks hands and start getting some feedback. Right now it's pretty abstracted and opt-in at the link level. We're hoping that once folks start using it we can figure out what other types of complex use-cases exist that we can't yet handle with these APIs.

There are 2 new APIs

• unstable_viewTransition flag on Link/NavLink/navigate/submit which enables the usage of document.startViewTransition for that navigation
  • Link docs
  • NavLink docs
• unstable_useViewTransitionState(to) - a hook that tells you if there is an active transition to the indicated location (or from a POP/reverse PUSH navigation)
  • Docs

Please see the changeset and docs for more info.

Live demo: https://github.com/brophdawg11/react-router-records

TODO:

• Unit tests

[changeset-bot]

🦋 Changeset detected

Latest commit: f3db06f

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

This PR includes changesets to release 5 packages

Name	Type
react-router-dom	Minor
react-router	Minor
@remix-run/router	Minor
react-router-dom-v5-compat	Minor
react-router-native	Minor

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[github-actions]

🤖 Hello there,

We just published version 6.17.0-pre.0 which includes this pull request. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!

[github-actions]

🤖 Hello there,

We just published version 6.17.0 which includes this pull request. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!