Fix index

Thanks to Ryo Suzuki
https://stacks.math.columbia.edu/tag/0GUB#comment-8100

chow.tex

@@ -5947,7 +5947,7 @@ \section{Affine bundles}
 is contained in an open $V \subset Y$ such that
 $f^{-1}(V) \cong V \times \mathbf{A}^r$ as schemes over $V$.
 In this remark we sketch a proof of the fact that
-$f^* : \CH_k(Y) \to \CH_k(X)$ is an isomorphism.
+$f^* : \CH_k(Y) \to \CH_{k + r}(X)$ is an isomorphism.
 First, by Lemma \ref{lemma-pullback-affine-fibres-surjective}
 the map is surjective. Let $\alpha \in \CH_k(Y)$ with $f^*\alpha = 0$.
 We will prove that $\alpha = 0$.