React Router hyperlinks can't be reached

## Summary

I found the wrong hyperlinks at the React Router [welcome page](https://devdocs.io/react_router/)

## Actual style

The hyperlinks use `https://reactrouterdotcom.fly.dev/` domain in all main sections of React router docs.
This domain cannot be reached anymore.

The current official [docs](https://reactrouter.com/en/main) of React Router is `https://reactrouter.com/en/main`