Flip components for consistency

THanks to Jia Jia
https://stacks.math.columbia.edu/tag/0264#comment-6292

spaces.tex

@@ -1322,7 +1322,7 @@ \section{Algebraic spaces and equivalence relations}
 
 \begin{proof}
 By Groupoids, Lemma \ref{groupoids-lemma-restrict-relation}
-the morphism $j' = (t', s') : R' \to U' \times_S U'$
+the morphism $j' = (s', t') : R' \to U' \times_S U'$
 defines an equivalence relation. Since $g$ is flat and locally of
 finite presentation we see that $g$ is universally open as well
 (Morphisms, Lemma \ref{morphisms-lemma-fppf-open}).