message: docs(react): add instructions on how to exit app via hardware back button
diff: @@ -168,8 +168,8 @@ In some scenarios, it may be desirable to quit the app when pressing the hardwar
  <docs-tab tab="javascript">
  ```typescript
  -import { Plugins } from '@capacitor/core';
  import { BackButtonEvent } from '@ionic/core';
  +import { Plugins } from '@capacitor/core';
  const { App } = Plugins;
  ...
  @@ -205,13 +205,33 @@ constructor(
  });
  }
  +```
  +</docs-tab>
  +<docs-tab tab="react">
  +
  +```typescript
  +import { useIonRouter } from '@ionic/react';
  +import { Plugins } from '@capacitor/core';
  +const { App } = Plugins;
  +
  +...
  +
  +const ionRouter = useIonRouter();
  +document.addEventListener('ionBackButton', (ev) => {
  + ev.detail.register(-1, () => {
  + if (!ionRouter.canGoBack()) {
  + App.exitApp();
  + }
  + });
  +});
  +
  ```
  </docs-tab>
  </docs-tabs>
  This example shows the application exiting when the user presses the hardware back button and there is nothing left in the navigation stack. It is also possible to display a confirmation dialog before quitting the app.
  -It is recommended to check whether or not the user is on the root page prior to exiting the application. Developers can use the `canGoBack` method on `IonRouterOutlet` in Ionic Angular. Support for this will be coming to Ionic React soon.
  +It is recommended to check whether or not the user is on the root page prior to exiting the application. Developers can use the `canGoBack` method on `IonRouterOutlet` in Ionic Angular and `IonRouter` in Ionic React.
  ## Internal Framework Handlers
  