RP guidance for invalidStateError returned from [[Create]]()

[equalsJeffH]

the Note that PR #1326 inserts into the spec explains the purpose of the UV gesture solicited in the authenticatorMakeCredential() operation when there are match(es) in the |excludeCredentialDescriptorList|. Essentially, we're explaining in the (new) Note that: "if the RP gets an invalidStateError back from a nav.creds.Create() call, they can do something user-helpful with that info".

However, this guidance for the RP is buried in "Note:"s in spec sections that we are not suggesting RP devs read (i.e., in the spec roadmap).

Additionally, our "RP Ops - registering a new cred" section only says "abort the ceremony with a user-visible error" if an error is returned from Create().

Seems like we ought to provide more guidance to the RP reader. Perhaps add this to the "rp operations - registering a new cred" section ?

Are there also similar RP considerations for "RP Ops - verifying an authentication assertion" we ought to add to the latter section?

[equalsJeffH]

this is a nice-to-have issue, can be addressed in a milestone later than wd-03 or not at all.

[equalsJeffH]

@sbweeden -- what's your take on this issue? Is it worth addressing? If so, might you as an RP have wording suggestions?

[sbweeden]

Closing - addressed with #1502