Usage: gms_chat_get_time ( n )
Returns the time at which message n was received or sent. Basically, it's the variable 'current_time,' saved when the message was sent.
If the player sent the message himself, the time at which the message was sent will be returned. If the message was sent by another player, the time at which the message was received will be returned. If the message doesn't exist, 0 will be returned.