fix linting

Author: paulbastian

draft-ietf-oauth-attestation-based-client-auth.md

@@ -407,7 +407,7 @@ To validate a client attestation using the concatenated serialization form, the
 # Nonce Retrieval
 
 This specification defines header fields that allow a Client to request a fresh nonce value to be used in the OAuth-Client-Attestation-PoP.
-An Authorization Server compliant with this specification SHOULD signal via metadata whether a server-provided nonce MUST be used by the client. 
+An Authorization Server compliant with this specification SHOULD signal via metadata whether a server-provided nonce MUST be used by the client.
 
 A Request to an endpoint from the AS can include the `attestation-nonce-request` field name with the value `true`. The server answers with a HTTP Response with status code 200, no payload, and the header field name `attestation-nonce` and value equal to the nonce.