Mention that the screenshot button is not supported on the web

Author: antonis

docs/platforms/react-native/user-feedback/configuration/index.mdx

@@ -289,6 +289,12 @@ The capture screenshot button can be customized too. The following styles are av
 | `triggerText`   | `TextStyle`  | The screenshot button text style. |
 | `triggerIcon`   | `ImageStyle` | The screenshot button icon style. |
 
+<Alert>
+
+Note that the screenshot button is currently not supported on the web.
+
+</Alert>
+
 ## Theming
 
 You can also customize the Feedback Widget colors to match your app's theme. The example below shows how to customize the widget background and foreground for the light and dark system themes with the `feedbackIntegration`.