fix link to ReactDOMHostconfig in reconciler docs (#25788)

## Summary

Reference to #25716, changed old link to a new, now page exist, instead
of 404.

## How did you test this change?

yarn test
and by clicking on the link of host config in
https://github.com/facebook/react/blob/main/packages/react-reconciler/README.md#practical-examples

packages/react-reconciler/README.md

@@ -58,7 +58,7 @@ The React repository includes several renderers. Each of them has its own host c
 The examples in the React repository are declared a bit differently than a third-party renderer would be. In particular, the `HostConfig` object mentioned above is never explicitly declared, and instead is a *module* in our code. However, its exports correspond directly to properties on a `HostConfig` object you'd need to declare in your code:
 
 * [React ART](https://github.com/facebook/react/blob/main/packages/react-art/src/ReactART.js) and its [host config](https://github.com/facebook/react/blob/main/packages/react-art/src/ReactARTHostConfig.js)
-* [React DOM](https://github.com/facebook/react/blob/main/packages/react-dom/src/client/ReactDOM.js) and its [host config](https://github.com/facebook/react/blob/main/packages/react-dom/src/client/ReactDOMHostConfig.js)
+* [React DOM](https://github.com/facebook/react/blob/main/packages/react-dom/src/client/ReactDOM.js) and its [host config](https://github.com/facebook/react/blob/main/packages/react-dom-bindings/src/client/ReactDOMHostConfig.js)
 * [React Native](https://github.com/facebook/react/blob/main/packages/react-native-renderer/src/ReactNativeRenderer.js) and its [host config](https://github.com/facebook/react/blob/main/packages/react-native-renderer/src/ReactNativeHostConfig.js)
 
 If these links break please file an issue and we’ll fix them. They intentionally link to the latest versions since the API is still evolving. If you have more questions please file an issue and we’ll try to help!