fix docs link for useSyncExternalStore (#26452)

## Summary

Update readme to new documentation links to
[`React.useSyncExternalStore`](https://react.dev/reference/react/useSyncExternalStore

## How did you test this change?

This is just a documentation change, so we don't need to test it

Co-authored-by: 田源 <[email protected]>

Author: sdta25196

packages/use-subscription/README.md

@@ -2,7 +2,7 @@
 
 React Hook for subscribing to external data sources.
 
-**You may now migrate to [`use-sync-external-store`](https://www.npmjs.com/package/use-sync-external-store) directly instead, which has the same API as [`React.useSyncExternalStore`](https://reactjs.org/docs/hooks-reference.html#usesyncexternalstore). The `use-subscription` package is now a thin wrapper over `use-sync-external-store` and will not be updated further.**
+**You may now migrate to [`use-sync-external-store`](https://www.npmjs.com/package/use-sync-external-store) directly instead, which has the same API as [`React.useSyncExternalStore`](https://react.dev/reference/react/useSyncExternalStore). The `use-subscription` package is now a thin wrapper over `use-sync-external-store` and will not be updated further.**
 
 # Installation