Add refresh token service support for union-type returning endpoints (#1132)

* support refresh tokens in union-type endpoints

CreateTokenWith<TService, TTokenResponse> decouples the token response type
from the endpoint's TResponse, so endpoints returning a union-type result
(e.g. Results<Ok<TokenResponse>, UnauthorizedHttpResult>) can mint tokens.
The existing single-generic overload now delegates to it. Resolves #597.

* add xml comments

* change editorconfig and gitattributes

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Co-authored-by: Dĵ ΝιΓΞΗΛψΚ <dj-nitehawk@users.noreply.github.com>
Co-authored-by: Dĵ ΝιΓΞΗΛψΚ <djnitehawk83@gmail.com>