fix master/doc/groovy/AutoTranslation.ipynb

[jimmybow]

fix doc/groovy/AutoTranslation.ipynb
target = ((int) log(1 + r.nextInt(nnodes))/log(1.3))
to
target = (int) (log(1 + r.nextInt(nnodes))/log(1.3))

https://github.com/twosigma/beakerx/blob/master/doc/groovy/AutoTranslation.ipynb?short_path=079d141#L42