driver sync additional_key information

[yugecin]

probably interesting to note under ID_DRIVER_SYNC's (all sync packets that have this) "Additional Information" that additional_key value 3 is supposed to be interpreted as 4 because there's only 2 bits but it sends 3 keys where the third key uses both bits set, and the keys of bit 1 and 2 can never be active together.

that's probably a shit explanation but:

actual_keys = packet.keys | (packet.additional_key == 3 ? 0x40000 : packet.additional_key << 16)

[NexiusTailer]

Finally added this too, in a single place under its own subsection:
https://github.com/Brunoo16/samp-packet-list/wiki/Packet-List#additional-key-encoding