RGBDS syntax updates (#905)

New MACRO and DEF syntax

constants/trainer_data_constants.asm

@@ -1,11 +1,11 @@
 ; TrainerClassAttributes struct members (see data/trainers/attributes.asm)
 rsreset
-TRNATTR_ITEM1           rb ; 0
-TRNATTR_ITEM2           rb ; 1
-TRNATTR_BASEMONEY       rb ; 2
-TRNATTR_AI_MOVE_WEIGHTS rw ; 3
-TRNATTR_AI_ITEM_SWITCH  rw ; 5
-NUM_TRAINER_ATTRIBUTES EQU _RS
+DEF TRNATTR_ITEM1           rb ; 0
+DEF TRNATTR_ITEM2           rb ; 1
+DEF TRNATTR_BASEMONEY       rb ; 2
+DEF TRNATTR_AI_MOVE_WEIGHTS rw ; 3
+DEF TRNATTR_AI_ITEM_SWITCH  rw ; 5
+DEF NUM_TRAINER_ATTRIBUTES EQU _RS
 
 ; TRNATTR_AI_MOVE_WEIGHTS bit flags (wEnemyTrainerAIFlags)
 ; AIScoringPointers indexes (see engine/battle/ai/move.asm)
@@ -20,7 +20,7 @@ NUM_TRAINER_ATTRIBUTES EQU _RS
 	shift_const AI_CAUTIOUS
 	shift_const AI_STATUS
 	shift_const AI_RISKY
-NO_AI EQU 0
+DEF NO_AI EQU 0
 
 ; TRNATTR_AI_ITEM_SWITCH bit flags
 	const_def
@@ -32,12 +32,12 @@ NO_AI EQU 0
 	const UNKNOWN_USE_F      ; 5
 	const CONTEXT_USE_F      ; 6
 
-SWITCH_OFTEN       EQU 1 << SWITCH_OFTEN_F
-SWITCH_RARELY      EQU 1 << SWITCH_RARELY_F
-SWITCH_SOMETIMES   EQU 1 << SWITCH_SOMETIMES_F
-ALWAYS_USE         EQU 1 << ALWAYS_USE_F
-UNKNOWN_USE        EQU 1 << UNKNOWN_USE_F
-CONTEXT_USE        EQU 1 << CONTEXT_USE_F
+DEF SWITCH_OFTEN       EQU 1 << SWITCH_OFTEN_F
+DEF SWITCH_RARELY      EQU 1 << SWITCH_RARELY_F
+DEF SWITCH_SOMETIMES   EQU 1 << SWITCH_SOMETIMES_F
+DEF ALWAYS_USE         EQU 1 << ALWAYS_USE_F
+DEF UNKNOWN_USE        EQU 1 << UNKNOWN_USE_F
+DEF CONTEXT_USE        EQU 1 << CONTEXT_USE_F
 
 ; TrainerTypes indexes (see engine/battle/read_trainer_party.asm)
 	const_def