Fix typo in Ed448 signature format
The native format in RFC 8032 is 114 octets long, as specified also here: https://gitlab.com/openpgp-wg/rfc4880bis/-/blob/main/crypto-refresh.md#L3132
The native format in RFC 8032 is 114 octets long, as specified also here: https://gitlab.com/openpgp-wg/rfc4880bis/-/blob/main/crypto-refresh.md#L3132