Simplify text in section on JWT Authorization Grant

[PieterKas]

JWT Authorization Grant

The client presents the JWT authorization grant it received from the authorization server in trust domain A as an authorization grant to the authorization server in trust domain B to obtain an access token for a resource server in trust domain B. The authorization grant is presented as defined inthe JWT Profile for OAuth 2.0 Client Authentication and Authorization Grants {{RFC7523}}.

Access Token Request

The authorization grant is a JWT bearer token, which the client in trust domain A uses to request an access token from the authorization server in trust domain B as described in the JWT Profile for OAuth 2.0 Client Authentication and Authorization Grants {{RFC7523}}. For the purpose of this specification the following descriptions apply: