"Forged", when refering to a hook, means that it's flattened from side to side; i.e. not round in cross section but more of an oval, taller than wide.
It has nothing to do with how the hook was sharpened.
Forged hooks are presumedly more resistant than a hook that's round in cross section for the same weight of wire.
There's no reason that a forged hook can't also be chemically sharped, but I've never used any if they are in fact made.