Fix incorrect link in README to auth state changes (#687)
Fix incorrect link in README to auth state changes (#687)

* Fix incorrect link in README to auth state changes

* Add clarification to README

* Fix typo

SUPERCILEX/FirebaseUI-Android,firebase/FirebaseUI-Android,SUPERCILEX/FirebaseUI-Android,samtstern/FirebaseUI-Android,SUPERCILEX/FirebaseUI-Android,JosefHruska/FirebaseUI-Android,firebase/FirebaseUI-Android,firebase/FirebaseUI-Android,samtstern/FirebaseUI-Android,firebase/FirebaseUI-Android,SUPERCILEX/FirebaseUI-Android,JosefHruska/FirebaseUI-Android,samtstern/FirebaseUI-Android