docs(ui_auth): add docs links to the package README (#10104)

add naming conflicts resolution instructions

Author: lesnitsky

packages/firebase_ui_auth/README.md

@@ -28,13 +28,13 @@ Firebase UI Auth is a set of Flutter widgets and utilities designed to help you
 flutter pub add firebase_ui_auth
 ```
 
-## Getting Started
+## Example
 
 Here's a quick example that shows how to build a `SignInScreen` and `ProfileScreen` in your app
 
 ```dart
 import 'package:flutter/material.dart';
-import 'package:firebase_auth/firebase_auth.dart';
+import 'package:firebase_auth/firebase_auth.dart' hide EmailAuthProvider;
 import 'package:firebase_ui_auth/firebase_ui_auth.dart';
 
 class MyApp extends StatelessWidget {
@@ -71,7 +71,18 @@ class MyApp extends StatelessWidget {
 }
 ```
 
-Learn more [here](https://github.com/firebase/flutterfire/tree/master/packages/firebase_ui_auth/doc).
+## Docs
+
+Find relevant documentation [here](https://github.com/firebase/flutterfire/tree/master/packages/firebase_ui_auth/doc)
+
+- [Getting started](https://github.com/firebase/flutterfire/tree/master/packages/firebase_ui_auth/doc)
+- Auth providers.
+  - [Email auth provider](https://github.com/firebase/flutterfire/blob/master/packages/firebase_ui_auth/doc/providers/email.md) – sign in using email and password.
+  - [Email verification](https://github.com/firebase/flutterfire/blob/master/packages/firebase_ui_auth/doc/providers/email-verification.md) - verify email.
+  - [Email link sign in](https://github.com/firebase/flutterfire/blob/master/packages/firebase_ui_auth/doc/providers/email-link.md) - sign in using a link sent to email.
+  - [Phone auth provider](https://github.com/firebase/flutterfire/blob/master/packages/firebase_ui_auth/doc/providers/phone.md) - sign in using phone number.
+  - [Universal email sign in](https://github.com/firebase/flutterfire/blob/master/packages/firebase_ui_auth/doc/providers/universal-email-sign-in.md) - resolve connected providers based on email and sign in using one of those.
+  - [OAuth](https://github.com/firebase/flutterfire/blob/master/packages/firebase_ui_auth/doc/providers/oauth.md) - sign in using Apple, Google, Facebook or Twitter.
 
 ## Roadmap / Features
 

packages/firebase_ui_auth/doc/providers/email-link.md

@@ -1,4 +1,4 @@
-# Firebase UI Email provider
+# Firebase UI Email Link provider
 
 ## Configuration
 

packages/firebase_ui_auth/doc/providers/email.md

@@ -13,6 +13,9 @@ Configure email provider:
 import 'package:firebase_core/firebase_core.dart';
 import 'package:firebase_ui_auth/firebase_ui_auth.dart';
 
+// If you need to use FirebaseAuth directly, make sure to hide EmailAuthProvider:
+// import 'package:firebase_auth/firebase_auth.dart' hide EmailAuthProvider;
+
 import 'firebase_options.dart';
 
 void main() {

packages/firebase_ui_auth/doc/providers/oauth.md

@@ -2,8 +2,9 @@
 
 ## Google Sign In
 
-To support Google as a provider, first install the official [`google_sign_in`](https://pub.dev/packages/google_sign_in)
-plugin to your project as described in the README.
+To support Google as a provider, first install the official [`google_sign_in`](https://pub.dev/packages/google_sign_in) plugin to your project as described in the README.
+
+❗️ Important: you need go through configuration steps for each platform as described on the [README](https://pub.dev/packages/google_sign_in).
 
 Next, enable the "Google" provider in the Firebase Console:
 
@@ -40,11 +41,7 @@ See [Custom screens section](#custom-screens) to learn how to use a button on yo
 
 ## Sign in with Apple
 
-To support Apple as a provider, first install the [`sign_in_with_apple`](https://pub.dev/packages/sign_in_with_apple)
-plugin to your project. Once added, follow the [Integration](https://pub.dev/packages/sign_in_with_apple#integration) steps
-for each platform.
-
-Next, enable the "Apple" provider in the Firebase Console:
+To support Apple as a provider, enable the "Apple" provider in the Firebase Console:
 
 ![Enable Apple Provider](../images/ui-apple-provider.jpg)
 
@@ -109,7 +106,7 @@ See [Custom screens section](#custom-screens) to learn how to use a button on yo
 ## Twitter Login
 
 To support Twitter as a provider, first install the [`twitter_login`](https://pub.dev/packages/twitter_login)
-plugin to your project.
+plugin to your project and make sure you've performed necessary configuration as described on [README](https://pub.dev/packages/twitter_login).
 
 Next, enable the "Twitter" provider in the Firebase Console:
 

packages/firebase_ui_auth/doc/providers/phone.md

@@ -14,6 +14,10 @@ Configure phone provider:
 
 ```dart
 import 'package:firebase_core/firebase_core.dart';
+import 'package:firebase_ui_auth/firebase_ui_auth.dart';
+
+// If you need to use FirebaseAuth directly, make sure to hide PhoneAuthProvider:
+// import 'package:firebase_auth/firebase_auth.dart' hide PhoneAuthProvider;
 
 void main() {
   WidgetsFlutterBinding.ensureInitialized();