Ok, I figured it out, I'll post it below so that anyone who needs it can use it, Maybe you could also add it to the list on the FAQ?
$attachment "Name of attachment" "Name of bone" 0 0 0 rotate 0 0 0
attachment_point Name of attachment
Where it says "Name of" is up to you to name, for the "Name of bone" you put the name of the bone that you want the particles attached to, and the three zeros after it offset the location that the particles spawn from, the first zero goes left/right, the second goes up/down, the third goes forward/backward,
The three zeros after those are for rotation, but I do not know which slot rotates it which direction, but I am sure you can figure it out just by playing with it a little.
You can read more about the $attachment command here: https://developer.valvesoftware.com/wiki/$attachment