Accepting code review suggestion

Author: charlesschaefer

src/content/docs/plugin/biometric.mdx

@@ -215,6 +215,10 @@ fn bio_auth(app_handle: tauri::AppHandle) {
 
 ### Biometric protected cryptography
 
+:::caution[Android-only feature]
+This feature is available only for Android.
+:::
+
 To encrypt/decrypt data using an asymmetric cryptography method that is protected behind the user Biometric Authentication, utilize the `biometricCipher()` method.
 
 <Tabs syncKey="lang">