Fix: Changed token=>tokenString in the AccessToken, for firebase-auth.md

website/docs/firebase-auth.md

@@ -9,7 +9,7 @@ Future<UserCredential?> signInWithFacebook() async {
   final LoginResult result = await FacebookAuth.instance.login();
   if(result.status == LoginStatus.success){
     // Create a credential from the access token
-    final OAuthCredential credential = FacebookAuthProvider.credential(result.accessToken!.token);
+    final OAuthCredential credential = FacebookAuthProvider.credential(result.accessToken!.tokenString);
     // Once signed in, return the UserCredential
     return await FirebaseAuth.instance.signInWithCredential(credential);
   }