z_player.c: enum for trade item identification

[GhostlyDark]

Use the enum value from item.h instead of the hardcoded 0x18, which equals the first bottle item, seemingly for identifying trade items.

[GhostlyDark]

Format check appears to be hung up on other files:

+ M src/audio/game/sequence.c
+ M src/boot/inflate.c
+ M src/code/gDPLoadTextureBlock_Runtime.inc.c
+ M src/code/mempak.c
+ M src/code/z_camera.c
+ M src/code/z_vr_box.c
+ M src/libu64/loadfragment2_n64.c
+ M src/libu64/relocation_gc.c
+ M src/overlays/actors/ovl_En_Mag/z_en_mag.c

[Dragorn421]

We use clang-format-14 specifically, probably you have a more recent version installed which would explain the differences and why the format check fails

[djevangelia]

This is correct, it looks a bit awkward but this allows using PLAYER_IA enum to convert to EXCH_ITEM despite the fact that PLAYER_IA has the relevant bottle items before the other exchange items (and some non-trade bottle items inbetween) and EXCH_ITEM has bottle items after other exchange items.