book2 suppl: typo in the formula on page 66 line 26

[slonik-az]

In the book-2 supplementary materials version draft August 12, 2022 the formula on the page 66 line 26 is missing a term in the brackets. It should read

$$ \log(\sigma(x)) = -\log(1+e^{-x}) = ... $$

In the current version the number $1$ is missing.