There were a lot of unused labels in there, and a few confusing
misnomers around move_effects_pointers.asm. They now match up exactly
with the names in battle_constants.asm.
Also renamed a few effects, to make their purpose clearer, and to match
up with their respective event script commands:
EFFECT_EXPLOSION -> EFFECT_SELFDESCTRUCT
EFFECT_HAZE -> EFFECT_RESET_STATS
EFFECT_WHIRLWIND -> EFFECT_FORCE_SWITCH
EFFECT_BIND -> EFFECT_TRAP_TARGET
EFFECT_TWINEEDLE -> EFFECT_POISON_MULTI_HIT
EFFECT_STEEL_WING -> EFFECT_DEFENSE_UP_HIT
EFFECT_METAL_CLAW -> EFFECT_ATTACK_UP_HIT
EFFECT_ANCIENTPOWER -> EFFECT_ALL_UP_HIT
