Fix typo

Thanks to Simon
https://stacks.math.columbia.edu/tag/01LC#comment-4729

schemes.tex

@@ -4733,9 +4733,9 @@ \section{Functoriality for quasi-coherent modules}
 $$
 where $\mathcal{F}_i, \mathcal{F}_{ijk}$ denotes the
 restriction of $\mathcal{F}$ to the corresponding open.
-If $\mathcal{F}$ is a quasi-coherent $\mathcal{O}_X$-modules
-then $\mathcal{F}_i$, $\mathcal{F}_{ijk}$ is a quasi-coherent
-$\mathcal{O}_{U_i}$, $\mathcal{O}_{U_{ijk}}$-module.
+If $\mathcal{F}$ is a quasi-coherent $\mathcal{O}_X$-module
+then $\mathcal{F}_i$ is a quasi-coherent $\mathcal{O}_{U_i}$-module
+and $\mathcal{F}_{ijk}$ is a quasi-coherent $\mathcal{O}_{U_{ijk}}$-module.
 Hence by Lemma \ref{lemma-widetilde-pullback} we see that the second and
 third term of the exact sequence are quasi-coherent
 $\mathcal{O}_S$-modules. Thus we conclude that