Original document suggested users to fall back to rsa key since ed25519 isn't supported. Change it to fall back to ecdsa. Reason: for anyone with ed25519 key, he must have deliberately avoided the default rsa key, hence it's better to suggest something other than rsa. ecdsa is in the same school (ECC) and is supported.
(also be specific that the user won't be asked root password - since the user might be asked the key's passphrase)
Original document suggested users to fall back to rsa key since ed25519 isn't supported. Change it to fall back to ecdsa. Reason: for anyone with ed25519 key, he must have deliberately avoided the default rsa key, hence it's better to suggest something other than rsa. ecdsa is in the same school (ECC) and is supported.
(also be specific that the user won't be asked root password - since the user might be asked the key's passphrase)