Fix typo

Thanks to Fabrice Orgogozo
https://stacks.math.columbia.edu/tag/09ZC#comment-4216

etale-cohomology.tex

@@ -13328,7 +13328,7 @@ \section{Schemes with strictly henselian local rings}
 
 \medskip\noindent
 Let $X = \Spec(R)$. Let $I \subset R$ be the set of elements
-$f \in R$ sch that $\xi|_{Z \cap D(f)} = 0$.
+$f \in R$ such that $\xi|_{Z \cap D(f)} = 0$.
 All local rings of $Z$ are strictly henselian
 by Lemma \ref{lemma-normal-scheme-with-alg-closed-function-field}
 and