anchor.diff:  
   [NOTE]
   `OAuth2UserService` is responsible for obtaining the user attributes
  -of the end user (the resource owner) from the `UserInfo` endpoint (byusing the
  +of the end user (the resource owner) from the UserInfo Endpoint (by using the
   access token granted to the client during the authorization flow)
   and return an `AuthenticatedPrincipal` in the form of an `OidcUser`.
   
  
positive.code: <1> `registrationId`: The ID that uniquely identifies the `ClientRegistration`.
  <2> `clientId`: The client identifier.
  <3> `clientSecret`: The client secret.
  <4> `clientAuthenticationMethod`: tThe method used to authenticate the Client with the Provider. The supported values are *basic* and *post*.
  <5> `authorizationGrantType`: The OAuth 2.0 Authorization Framework defines four https://tools.ietf.org/html/rfc6749#section-1.3[Authorization Grant] types.
   The supported values are authorization_code and implicit.
  <6> `redirectUriTemplate`: The client's registered redirect URI that the _Authorization Server_ redirects the end-user's user-agent
  
negative.code: This repository provides the ability to retrieve a sub-set of the primary client registration information,
  which is stored with the Authorization Server.
  
  Spring Boot 2.0 auto-configuration binds each of the properties under `spring.security.oauth2.client.registration._[registrationId]_`
  to an instance of `ClientRegistration` and then composes each of the `ClientRegistration` instance(s) within a `ClientRegistrationRepository`.
  
  [NOTE]
  