docs(act.md): correct ReactDOM to ReactDOMClient (#7156)

* docs(act.md): correct ReactDOMClient to ReactDOM

* docs(act.md): switch the import to ReactDOMClient instead

Author: regchiu

src/content/reference/react/act.md

@@ -90,7 +90,7 @@ To test the render output of a component, wrap the render inside `act()`:
 
 ```js  {10,12}
 import {act} from 'react';
-import ReactDOM from 'react-dom/client';
+import ReactDOMClient from 'react-dom/client';
 import Counter from './Counter';
 
 it('can render and update a counter', async () => {
@@ -99,7 +99,7 @@ it('can render and update a counter', async () => {
 
   // ✅ Render the component inside act().
   await act(() => {
-    ReactDOM.createRoot(container).render(<Counter />);
+    ReactDOMClient.createRoot(container).render(<Counter />);
   });
 
   const button = container.querySelector('button');
@@ -119,7 +119,7 @@ To test events, wrap the event dispatch inside `act()`:
 
 ```js {14,16}
 import {act} from 'react';
-import ReactDOM from 'react-dom/client';
+import ReactDOMClient from 'react-dom/client';
 import Counter from './Counter';
 
 it.only('can render and update a counter', async () => {
@@ -174,4 +174,4 @@ global.IS_REACT_ACT_ENVIRONMENT=true
 
 In testing frameworks like [React Testing Library](https://testing-library.com/docs/react-testing-library/intro), `IS_REACT_ACT_ENVIRONMENT` is already set for you.
 
-</Note>
+</Note>