Correct some map object-related constant names and a comment

constants/map_object_constants.asm

@@ -59,11 +59,11 @@ DEF OW_RIGHT EQU RIGHT << 2
 	shift_const LOW_PRIORITY   ; 0
 	shift_const HIGH_PRIORITY  ; 1
 	shift_const BOULDER_MOVING ; 2
-	shift_const OVERHEAD       ; 3
+	shift_const IN_GRASS       ; 3
 	shift_const USE_OBP1       ; 4
 	shift_const FROZEN         ; 5
 	shift_const OFF_SCREEN     ; 6
-	shift_const OBJ_FLAGS2_7   ; 7
+	shift_const UNDER_TILES    ; 7
 
 ; object_struct OBJECT_PALETTE bit flags
 	const_def 5

engine/overworld/map_objects.asm

@@ -226,7 +226,7 @@ CopyLastCoordsToCoords:
 UpdateTallGrassFlags:
 	ld hl, OBJECT_FLAGS2
 	add hl, bc
-	bit OVERHEAD_F, [hl]
+	bit IN_GRASS_F, [hl]
 	jr z, .ok
 	ld hl, OBJECT_TILE_COLLISION
 	add hl, bc
@@ -252,13 +252,13 @@ SetTallGrassFlags:
 .set
 	ld hl, OBJECT_FLAGS2
 	add hl, bc
-	set OVERHEAD_F, [hl]
+	set IN_GRASS_F, [hl]
 	ret
 
 .reset
 	ld hl, OBJECT_FLAGS2
 	add hl, bc
-	res OVERHEAD_F, [hl]
+	res IN_GRASS_F, [hl]
 	ret
 
 UselessAndA:
@@ -1144,7 +1144,7 @@ StepFunction_NPCJump:
 	call GetNextTile
 	ld hl, OBJECT_FLAGS2
 	add hl, bc
-	res OVERHEAD_F, [hl]
+	res IN_GRASS_F, [hl]
 	call ObjectStep_IncAnonJumptableIndex
 	ret
 
@@ -1183,7 +1183,7 @@ StepFunction_PlayerJump:
 	call CopyCoordsTileToLastCoordsTile
 	ld hl, OBJECT_FLAGS2
 	add hl, bc
-	res OVERHEAD_F, [hl]
+	res IN_GRASS_F, [hl]
 	ld hl, wPlayerStepFlags
 	set PLAYERSTEP_STOP_F, [hl]
 	set PLAYERSTEP_MIDAIR_F, [hl]
@@ -1249,7 +1249,7 @@ StepFunction_TeleportFrom:
 	ld [hl], 16
 	ld hl, OBJECT_FLAGS2
 	add hl, bc
-	res OVERHEAD_F, [hl]
+	res IN_GRASS_F, [hl]
 	call ObjectStep_IncAnonJumptableIndex
 .DoSpinRise:
 	ld hl, OBJECT_ACTION
@@ -2898,17 +2898,17 @@ InitSprites:
 	and ~(1 << 7)
 	ldh [hCurSpriteTile], a
 	xor a
-	bit 7, [hl] ; tiles $80+ are in VRAM bank 0
+	bit 7, [hl] ; tiles $80+ are in VRAM bank 1
 	jr nz, .not_vram1
 	or OAM_BANK1
 .not_vram1
 	ld hl, OBJECT_FLAGS2
 	add hl, bc
 	ld e, [hl]
-	bit OBJ_FLAGS2_7_F, e
-	jr z, .not_priority
+	bit UNDER_TILES_F, e
+	jr z, .not_under_tiles
 	or OAM_PRIO
-.not_priority
+.not_under_tiles
 	bit USE_OBP1_F, e
 	jr z, .not_obp_num
 	or OAM_PAL1
@@ -2921,10 +2921,10 @@ InitSprites:
 	or d
 	ld d, a
 	xor a
-	bit OVERHEAD_F, e
-	jr z, .not_overhead
+	bit IN_GRASS_F, e
+	jr z, .not_in_grass
 	or OAM_PRIO
-.not_overhead
+.not_in_grass
 	ldh [hCurSpriteOAMFlags], a
 	ld hl, OBJECT_SPRITE_X
 	add hl, bc

engine/overworld/movement.asm

@@ -753,7 +753,7 @@ JumpStep:
 
 	ld hl, OBJECT_FLAGS2
 	add hl, bc
-	res OVERHEAD_F, [hl]
+	res IN_GRASS_F, [hl]
 
 	ld hl, OBJECT_ACTION
 	add hl, bc