Fix many messages and sounds

* adding message notice when trying to fold a non-empty box.
* Fix one typo in item_attack.dm
* gives attack_verbs and hitsound to briefcase and secure briefcase (lack of sound when attacking)
* Attacking grille with a lit weldingtool plays the correct welding sound.
* Fixes immunity to monkey bites while wearing a muzzle / monkey being able to bite while wearing a muzzle.

(Mob attack messages & sounds)
* Attacking dead simple animal now gives message and sound for human/monkey/larva/humanoid and attack w/ item. (similar to attacking a dead human)
* Fixes finishing blow from human on mouse not giving sound/message.
* Fixes lack of sound when attacking simple_animal/syndicate/melee with an item.
* Gives sound to goat attacks.
* Fixes monkeys not being able to attack simple animals (dead or alive).
* Monkey attack on slime now uses "bite" verb and plays sound.
* Fixes Monkey inability to attack slime, humanoid, monkey, larva unconscious or dead.
* Gives sound to monkey on Human attack.
* Fixes inability of larvas to bite humanoids, slimes, humans.