Make it explicit that tools can show the value of variables for asserts

chapters/equations.tex

@@ -506,6 +506,7 @@ \subsection{assert}\label{assert}
   \lstinline!condition! needs to be implicitly treated with \lstinline!noEvent! since otherwise events might be triggered that can lead to slightly changed simulation results.
   \end{nonnormative}
 \end{itemize}
+Tools may show more than the message for failed assertions, in particular the condition and the values of any variables used in it.
 
 \begin{nonnormative}
 The \lstinline!AssertionLevel.error! case can be used to avoid evaluating a model outside its limits of validity; for instance, a function to compute the saturated liquid temperature cannot be called with a pressure lower than the triple point value.