Replace single en-dash by pair of em-dashes around 'the iteration range'

chapters/statements.tex

@@ -256,9 +256,7 @@ \subsubsection{Implicit Iteration Ranges}\doublelabel{implicit-iteration-ranges}
 \end{lstlisting}
 \end{example}
 
-The size of an array -- the iteration range is evaluated on entry to the
-for-loop and the array size may not change during the execution of the
-for-loop.
+The size of an array --- the iteration range --- is evaluated on entry to the for-loop and the array size may not change during the execution of the for-loop.
 
 \subsubsection{Types as Iteration Ranges }\doublelabel{types-as-iteration-ranges}