docs: add a note on using react refresh plugin in backend integration guide

Author: yyx990803

docs/guide/backend-integration.md

@@ -35,6 +35,17 @@ If you want to serve the HTML using a traditional backend (e.g. Rails, Laravel)
 
    Also make sure the server is configured to serve static assets in the Vite working directory, otherwise assets such as images won't be loaded properly.
 
+   Note if you are using React with `@vitejs/plugin-react-refresh`, you'll also need to add this, since the plugin is not able to modify the HTML you are serving:
+
+   ```html
+   <script type="module">
+     import RefreshRuntime from "/@react-refresh"
+     RefreshRuntime.injectIntoGlobalHook(window) window.$RefreshReg$ = () => {}
+     window.$RefreshSig$ = () => (type) => type
+     window.__vite_plugin_react_preamble_installed__ = true
+   </script>
+   ```
+
 3. For production: after running `vite build`, a `manifest.json` file will be generated alongside other asset files. An example manifest file looks like this:
 
    ```json