feat: additional details on migrating Auth with examples (#6599)

* feat: add details and examples, rearrange

* feat: add details to forgotPassword flow

* feat: add details to remember/forget device

* feat: add details to currentUserInfo

* chore: clean up

* chore: add additional info on migrating essentialCredentials

* chore: cleanup, add v5/v6 headings

Author: erinleigh90

cspell.json

@@ -165,6 +165,7 @@
     "Auth.currentAuthenticatedUser",
     "Auth.federatedSignIn",
     "Auth0",
+    "authcurrentusercredentials",
     "authData",
     "Authenticator's",
     "Authenticator",