Remove unused useState import in StrictMode.md

Removed unused import of useState from React.

Author: emersonpisoni

src/content/reference/react/StrictMode.md

@@ -536,7 +536,7 @@ root.render(<App />);
 ```
 
 ```js
-import { useState, useEffect } from 'react';
+import { useEffect } from 'react';
 import { createConnection } from './chat.js';
 
 const serverUrl = 'https://localhost:1234';