Clean up IANA section

[c2bo]

We should clean up the IANA section a bit, especially https://drafts.oauth.net/draft-ietf-oauth-status-list/draft-ietf-oauth-status-list.html#name-media-type-registration needs some work imho. Can we remove the n/a parameters from that part or are they required?

[paulbastian]

I think it is the recommended way: https://datatracker.ietf.org/doc/html/rfc6838#section-5.6

[paulbastian]

Closed by #175