RGBDS syntax updates (#905)

New MACRO and DEF syntax

engine/overworld/map_objects.asm

@@ -2805,9 +2805,9 @@ ApplyBGMapAnchorToObjects:
 	pop hl
 	ret
 
-PRIORITY_LOW  EQU $10
-PRIORITY_NORM EQU $20
-PRIORITY_HIGH EQU $30
+DEF PRIORITY_LOW  EQU $10
+DEF PRIORITY_NORM EQU $20
+DEF PRIORITY_HIGH EQU $30
 
 InitSprites:
 	call .DeterminePriorities

engine/overworld/player_movement.asm

@@ -601,7 +601,7 @@ DoPlayerMovement::
 	ld [wWalkingTile], a
 	ret
 
-player_action: MACRO
+MACRO player_action
 ; walk direction, facing, x movement, y movement, tile collision pointer
 	db \1, \2, \3, \4
 	dw \5