typo (\cat{C} -> \cat{C}^\mathit{op}) (#330)

src/content/2.6/yoneda-embedding.tex

@@ -108,7 +108,7 @@ \section{The Embedding}
   and Colimits}). The co-Yoneda embedding defines the embedding of a
 category $\cat{C}$ in the category of presheaves. Its action on morphisms
 is given by:
-\[[\cat{C}, \Set](\cat{C}(-, a), \cat{C}(-, b)) \cong \cat{C}(a, b)\]
+\[[\cat{C}^\mathit{op}, \Set](\cat{C}(-, a), \cat{C}(-, b)) \cong \cat{C}(a, b)\]
 Again, mathematicians know a lot about the category of presheaves, so
 being able to embed an arbitrary category in it is a big win.