* Deleted sTMHMMoves array, TMs/HMs read moves from their secondaryId item field now
The unused "registrability" variable has been removed in order to preserve the size of the gItems array after turning the secondaryId variable into a u16.
* Made ItemIdToBattleMoveId return ITEM_NONE if an item that is not a TM/HM is passed through it
* Renamed IsMoveHm to IsMoveHM