Issuer and IssuerFingerprint are added to the hashed subpacket area; update documentation
This impacts all sign_*
methods (and perhaps other places, grep for Issuer). See for example the documentation for sign_direct_key
:
If neither an Issuer subpacket (set using SignatureBuilder::set_issuer, for instance) nor an Issuer Fingerprint subpacket (set using SignatureBuilder::set_issuer_fingerprint, for instance) is set, they are both added to the new Signature's unhashed subpacket area and set to the signer's KeyID and Fingerprint, respectively.