Arse Nath should not delimb, ever

[zjdtmkhzt]

As far as I could tell from the code, Rathen's Secret currently always has a 7% chance for each individual limb to detach, regardless of your butt status. Not having a butt simply lengthens the stun to 3 seconds instead of 2 and does some minor brute damage.

I have made a PR to change Rathen's Secret to only remove limbs if the person has not butt, but I think that perhaps it should also be changed to always remove exactly one limb in that situation, rather than having it be RNG.

https://github.com/goonstation/goonstation/pull/1192