Fix typos

Misc/Warm-Ups/mario.tex

@@ -40,7 +40,11 @@
 		A 11-way tie is possible, with a top score of 28:
 		\begin{itemize}
 			\item Four players finish $1^\text{st}$, $3^\text{ed}$, $11^\text{th}$, and $12^\text{th}$;
+
+			% spell:off
 			\item Four players finish $2^\text{nd}$, $4^\text{th}$, $9^\text{th}$, and $10^\text{th}$;
+			% spell:on
+
 			\item Two players finish fifth twice and seventh twice,
 			\item One player finishes sixth in each race.
 		\end{itemize}