Replace en-dash by colon after 'twice'

chapters/statements.tex

@@ -145,9 +145,7 @@ \subsubsection{Assignments from Called Functions with Multiple Results}\doublela
 (a, b, c) := f(1.0, 2.0);
 (x[1], x[2], x[1]) := f(3,4);
 \end{lstlisting}
-In the second example above \lstinline!x[1]! is assigned twice -- first
-with the first output and then with the third output. For that case the
-following will give the same result:
+In the second example above \lstinline!x[1]! is assigned twice: first with the first output, and then with the third output.  For that case the following will give the same result:
 \begin{lstlisting}[language=modelica]
 (, x[2], x[1]) := f(3,4);
 \end{lstlisting}