Fix typo

Thanks to Keenan Kidwell
http://stacks.math.columbia.edu/tag/0BY1#comment-1856

curves.tex

@@ -143,7 +143,7 @@ \section{Curves and function fields}
 $k(Y) \to k(X)$ in the category (1). Then we obtain a morphism $U \to Y$
 for some nonempty open $U \subset X$. By Lemma \ref{lemma-extend-over-dvr}
 this extends to all of $X$ and we obtain a morphism in the category (5).
-Thus we see that there is a fully faithfull functor (5)$\to$(1).
+Thus we see that there is a fully faithful functor (5)$\to$(1).
 
 \medskip\noindent
 To finish the proof we have to show that every $K/k$ in (1)