Fix type error

Thanks to Ingo Blechschmidt
http://stacks.math.columbia.edu/tag/08LW#comment-1552

sites.tex

@@ -8654,7 +8654,8 @@ \section{Subtopoi}
 Let $\mathcal{C}$ be a site. Let $\mathcal{F}$ be a sheaf on
 $\mathcal{C}$. The following are equivalent
 \begin{enumerate}
-\item $\mathcal{F}$ is a subobject of the final object of $\mathcal{C}$, and
+\item $\mathcal{F}$ is a subobject of the final object of
+$\Sh(\mathcal{C})$, and
 \item the topos $\Sh(\mathcal{C})/\mathcal{F}$ is a subtopos of
 $\Sh(\mathcal{C})$.
 \end{enumerate}