add a text that kid, jwk and x5c are mutually exclusive? x5c example in key attestation?

[Sakurann]

Should we preserve an example that uses the x5c parameter too given it is still a header parameter declared in the definition of the proof syntax here https://github.com/openid/OpenID4VCI/pull/389/files#diff-1f424614b35a9899813079f1b1f6218631a2aedd993368ccb89bb81a9eda0289R884

Originally posted by @tplooker in https://github.com/openid/OpenID4VCI/pull/389#discussion_r1838585744

[Sakurann]

also, don't we need a text that kid, jwk and x5c are mutually exclusive?

[OR13]

Don't forget x5u

[vafeini]

Maybe already discussed in another issue, sorry if so, but shouldn't the same kind of text be added for the case of jwt Proof Type?