🐛 Add missing link in readme

Author: LinusU

readme.md

@@ -2,7 +2,7 @@
 
 A Flutter plugin for authenticating a user with a web service, even if the web service is run by a third party. Most commonly used with OAuth2, but can be used with any web flow that can redirect to a custom scheme.
 
-In the background, this plugin uses [`ASWebAuthenticationSession`][ASWebAuthenticationSession] on iOS 12 and newer, `SFAuthenticationSession` on iOS 11, and [Chrome Custom Tabs][Chrome Custom Tabs] on Android.
+In the background, this plugin uses [`ASWebAuthenticationSession`][ASWebAuthenticationSession] on iOS 12 and newer, [`SFAuthenticationSession`][SFAuthenticationSession] on iOS 11, and [Chrome Custom Tabs][Chrome Custom Tabs] on Android.
 
 [ASWebAuthenticationSession]: https://developer.apple.com/documentation/authenticationservices/aswebauthenticationsession
 [SFAuthenticationSession]: https://developer.apple.com/documentation/safariservices/sfauthenticationsession