Improve use of palette macro and use PAL_* constants (#1087)

* Improve use of palette macro and use PAL_* constants

* Use proper constant for battle stats (#1088)

* Add suggestions about function names and variables

* Add colors macro

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Co-authored-by: vulcandth <vulcandth@gmail.com>

engine/tilesets/timeofday_pals.asm

@@ -168,14 +168,14 @@ FillWhiteBGColor:
 	ld e, a
 	ld a, [hli]
 	ld d, a
-	ld hl, wBGPals1 + 1 palettes
+	ld hl, wBGPals1 palette 1 color 0
 	ld c, 6
 .loop
 	ld a, e
 	ld [hli], a
 	ld a, d
 	ld [hli], a
-rept 6
+rept 3 colors
 	inc hl
 endr
 	dec c