Remove superflous emphasis

These words don't really seem to correspond to something deserving emphasis, and removing the emphasis makes the definition more readable.

chapters/synchronous.tex

@@ -200,8 +200,8 @@ \subsection{Clocks and Clocked Variables}\doublelabel{clocks-and-clocked-variabl
 
 \begin{definition}[Piecewise-constant variable]
 (See \autoref{discrete-time-expressions}.)  Variables $m(t)$ of base type \lstinline!Real!, \lstinline!Integer!, \lstinline!Boolean!, enumeration, and \lstinline!String! that are
-\emph{constant} inside each interval $t_{i} \leq t < t_{i+1}$ (i.e., piecewise constant continuous-time variables).  In other words, $m(t)$ \emph{changes}
-value \emph{only at events}: $m(t) = m(t_{i})$, for $t_{i} \leq t < t_{i+1}$.  Such variables depend continuously on time and they are discrete-time variables.
+\emph{constant} inside each interval $t_{i} \leq t < t_{i+1}$ (i.e., piecewise constant continuous-time variables).  In other words, $m(t)$ changes
+value only at events: $m(t) = m(t_{i})$, for $t_{i} \leq t < t_{i+1}$.  Such variables depend continuously on time and they are discrete-time variables.
 See \autoref{fig:piecewise-constant-variable}.
 \end{definition}