scrump projectile disapear on collision and better disappear graphics (closes #190)

objects/enemy/boss/scrump_projectile.gd

@@ -1,10 +1,26 @@
 extends "res://objects/enemy/enemy.gd"
 
 
-func _physics_process(delta):
-	position.x -= 80 * delta
+var speed: float = 80.0
 
-func _on_Hitbox_area_entered(area):
+
+func _physics_process(delta: float) -> void:
+	position.x -= speed * delta
+
+func _on_Hitbox_area_entered(area: Node) -> void:
 	._on_Hitbox_area_entered(area)
 	if area.is_in_group("player_hitbox"):
-		self.queue_free()
+		_stop()
+
+
+func _on_Hitbox_body_entered(body: Node) -> void:
+	if body is TileMap:
+		_stop()
+
+
+func _stop() -> void:
+	speed = 0.0
+	$Hitbox.queue_free()
+	for child in $Particles.get_children():
+		if child is CPUParticles2D:
+			child.emitting = false