[webauthn] Issue: attestation unmentioned in authenticatorMakeCredential operation marked as type:editorial

equalsJeffH has just labeled an issue for 
https://github.com/w3c/webauthn as "type:editorial":

== attestation unmentioned in authenticatorMakeCredential operation ==
attestation should be mention in the "when this operations is invoked"
 parag of https://w3c.github.io/webauthn/#op-make-cred


See https://github.com/w3c/webauthn/issues/114