Changes for shoot and shoot_arrow effects.

[PQguanfang]

• Added arrow_damage arg for shoot (arrow only) and shoot_arrow effect.
• Added effect arg for shoot_arrow effect.
• Removed launch-at-location arg for shoot_arrow effect.
• launch-at-location arg won't work for arrow projectile in shoot effect.
• This is because in my test, this will lead arrow can not hit the entity. Picture for this is here, the arrows just spawn at zombie near location and the entity never be damaged: