Third time's a charm: translating weight system description

Still trying to fix the same issue that I already tried to address in
commit e0b70b82cad9 ("Fix translation of weightsystem names") and before
in commit dc03b7e7d689 ("We need the correct context to translate event
names").

I missed the WeightModel. Hopefully this was indeed the real fix.

Fixes #312

(I know, I keep saying that)

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>