docs(AuthFlow): fix typo in component name

Author: samouss

docs/auth-flow.md

@@ -18,7 +18,7 @@ Most apps require that a user authenticate in some way to have access to data as
 ```js
 import { StackNavigator, SwitchNavigator } from 'react-navigation';
 
-// Implementation of HomeScreen, OtherScreen, SignInScreen, LoadingScreen
+// Implementation of HomeScreen, OtherScreen, SignInScreen, AuthLoadingScreen
 // goes here.
 
 const AppStack = StackNavigator({ Home: HomeScreen, Other: OtherScreen });
@@ -133,4 +133,4 @@ class HomeScreen extends React.Component {
 ```
 <a href="https://snack.expo.io/@react-navigation/auth-flow" target="blank" class="run-code-button">&rarr; Run this code</a>
 
-That's about all there is to it. At the moment, `SwitchNavigator` doesn't support animating between screens. Let us know if this is important to you [on Canny](https://react-navigation.canny.io/feature-requests).
+That's about all there is to it. At the moment, `SwitchNavigator` doesn't support animating between screens. Let us know if this is important to you [on Canny](https://react-navigation.canny.io/feature-requests).