docs(ui_auth): improve phone.md (#9774)

Author: Knupper

Diff for: AUTHORS

@@ -59,3 +59,4 @@ Alessandro Rossi <[email protected]>
 Timur Dyushaliev <[email protected]>
 Maaku Saito <[email protected]>
 Markus Köhne <[email protected]>
+Max Steffen <[email protected]>

Diff for: packages/firebase_ui_auth/doc/providers/phone.md

@@ -10,7 +10,7 @@ enabled in the [Firebase Console](https://console.firebase.google.com/project/_/
 Next, follow the [Setup Instructions](https://firebase.google.com/docs/auth/flutter/phone-auth) to configure Phone Authentication for your
 platforms.
 
-Configure email provider:
+Configure phone provider:
 
 ```dart
 import 'package:firebase_core/firebase_core.dart';
@@ -20,7 +20,7 @@ void main() {
   await Firebase.initializeApp(options: DefaultFirebaseOptions.currentPlatform);
 
   FirebaseUIAuth.configureProviders([
-    PhoneAuthProvider(),,
+    PhoneAuthProvider(),
     // ... other providers
   ]);
 }