Messed up the primes

Thanks to OS and William Chen
https://stacks.math.columbia.edu/tag/046S#comment-1813
https://stacks.math.columbia.edu/tag/046S#comment-3226

spaces-groupoids.tex

@@ -2629,13 +2629,13 @@ \section{Restriction and quotient stacks}
 $$
 [f] : [U/R] \longrightarrow [U'/R']
 $$
-is fully faithful if and only if $R'$ is the restriction of
-$R$ via the morphism $f : U \to U'$.
+is fully faithful if and only if $R$ is the restriction of
+$R'$ via the morphism $f : U \to U'$.
 \end{lemma}
 
 \begin{proof}
 Let $x, y$ be objects of $[U/R]$ over a scheme $T/S$.
-Let $x', y'$ be the images of $x, y$ in the category $[U'/'R]_T$.
+Let $x', y'$ be the images of $x, y$ in the category $[U'/R']_T$.
 The functor $[f]$ is fully faithful if and only if the map of sheaves
 $$
 \mathit{Isom}(x, y) \longrightarrow \mathit{Isom}(x', y')