Clean up bugs commented in the source code (#912)

Co-authored-by: Rangi <remy.oukaour+rangi42@gmail.com>

engine/overworld/overworld.asm

@@ -346,8 +346,7 @@ AddSpriteGFX:
 	ret
 
 LoadSpriteGFX:
-; Bug: b is not preserved, so it's useless as a next count.
-; Uncomment the lines below to fix.
+; BUG: LoadSpriteGFX does not limit the capacity of UsedSprites (see docs/bugs_and_glitches.md)
 
 	ld hl, wUsedSprites
 	ld b, SPRITE_GFX_LIST_CAPACITY
@@ -366,9 +365,7 @@ LoadSpriteGFX:
 	ret
 
 .LoadSprite:
-	; push bc
 	call GetSprite
-	; pop bc
 	ld a, l
 	ret