Make it slightly more clear that Curve25519 keys are treated as ECDH
While Ed25519 gets its own packet tag, Curve25519 keys are treated the same as ECDH (by design and by the GnuPG implementation).
While Ed25519 gets its own packet tag, Curve25519 keys are treated the same as ECDH (by design and by the GnuPG implementation).