Change section title to 'Continuous-Time and Non-Discrete-Time Expres…

…sions'

chapters/operatorsandexpressions.tex

@@ -1533,7 +1533,7 @@ \subsection{Discrete-Time Expressions}\label{discrete-time-expressions}
 \end{lstlisting}
 \end{example}
 
-\subsection{Continuous-Time Expressions}\label{continuous-time-expressions}
+\subsection{Continuous-Time and Non-Discrete-Time Expressions}\label{continuous-time-expressions}
 
 All expressions are continuous-time expressions\index{continuous-time!expression}\index{expression variability!continuous-time} including constant, parameter and discrete expressions.
 The term \firstuse{non-discrete-time expression}\index{non-discrete-time expression}\index{expression variability!non-discrete-time} refers to expressions that are neither constant, parameter nor discrete-time expressions.  For example, a continuous-time variable (see \cref{component-variability-prefixes-discrete-parameter-constant}) is a non-discrete-time expression.