Clean up one case of non-normative content that wasn't formatted with…

… \emph

chapters/equations.tex

@@ -656,9 +656,11 @@ \section{Events and Synchronization}\doublelabel{events-and-synchronization}
 All equations and assignment statements within when-clauses and all
 assignment statements within function classes are implicitly treated
 with the noEvent function, i.e., relations within the scope of these
-operators never induce state or time events. {[}Using state events in
-when-clauses is unnecessary because the body of a when-clause is not
-evaluated during continuous integration.{]}
+operators never induce state or time events.
+
+\begin{nonnormative}
+Using state events in when-clauses is unnecessary because the body of a when-clause is not evaluated during continuous integration.
+\end{nonnormative}
 
 \begin{example}
 \begin{lstlisting}[language=modelica]