docs: add dev command into doc

Author: nyqykk

website/docs/en/guide/advanced/module-federation.mdx

@@ -154,6 +154,7 @@ export default config;
 ### 3. Start writing stories
 
 ```ts title="stories/index.stories.tsx" {1-2}
+import React from 'react';
 // Load your remote module here, Storybook will act as the host app.
 import { Counter } from 'rslib-module';
 
@@ -181,7 +182,20 @@ export const Primary = {};
 }
 ```
 
-### 5. Start Storybook app
+### 5. Add Rslib `mf dev` command
+
+```json title="package.json"
+{
+  // ...
+  "scripts": {
+    "dev": "rslib mf dev"
+  }
+}
+```
+
+And run `npm run dev` to start Module Federation development mode
+
+### 6. Start Storybook app
 
 There you go, start Storybook with `npx storybook dev`.