RGBDS syntax updates (#905)

New MACRO and DEF syntax

constants/input_constants.asm

@@ -9,18 +9,18 @@
 	const D_UP_F     ; 6
 	const D_DOWN_F   ; 7
 
-NO_INPUT   EQU %00000000
-A_BUTTON   EQU 1 << A_BUTTON_F
-B_BUTTON   EQU 1 << B_BUTTON_F
-SELECT     EQU 1 << SELECT_F
-START      EQU 1 << START_F
-D_RIGHT    EQU 1 << D_RIGHT_F
-D_LEFT     EQU 1 << D_LEFT_F
-D_UP       EQU 1 << D_UP_F
-D_DOWN     EQU 1 << D_DOWN_F
+DEF NO_INPUT   EQU %00000000
+DEF A_BUTTON   EQU 1 << A_BUTTON_F
+DEF B_BUTTON   EQU 1 << B_BUTTON_F
+DEF SELECT     EQU 1 << SELECT_F
+DEF START      EQU 1 << START_F
+DEF D_RIGHT    EQU 1 << D_RIGHT_F
+DEF D_LEFT     EQU 1 << D_LEFT_F
+DEF D_UP       EQU 1 << D_UP_F
+DEF D_DOWN     EQU 1 << D_DOWN_F
 
-BUTTONS    EQU A_BUTTON | B_BUTTON | SELECT | START
-D_PAD      EQU D_RIGHT | D_LEFT | D_UP | D_DOWN
+DEF BUTTONS    EQU A_BUTTON | B_BUTTON | SELECT | START
+DEF D_PAD      EQU D_RIGHT | D_LEFT | D_UP | D_DOWN
 
-R_DPAD     EQU %00100000
-R_BUTTONS  EQU %00010000
+DEF R_DPAD     EQU %00100000
+DEF R_BUTTONS  EQU %00010000