etale at x not X

Thanks to Fei Hu
https://stacks.math.columbia.edu/tag/0EA3#comment-3243

pione.tex

@@ -5682,7 +5682,7 @@ \section{Purity of ramification locus}
 \item $\mathcal{O}_{X, x}$ is normal of dimension $2$,
 \item $f$ is \'etale outside of $\overline{\{x\}}$.
 \end{enumerate}
-Then $f$ is \'etale at $X$.
+Then $f$ is \'etale at $x$.
 \end{lemma}
 
 \begin{proof}