Update chapters/statemachines.tex

Co-authored-by: Henrik Tidefelt <henrikt@wolfram.com>

chapters/statemachines.tex

@@ -358,7 +358,7 @@ \subsection{Reset Handling}\label{reset-handling}
 
 \subsection{Activation handling}\label{activation-handling}
 
-When a state is suspended its equations should not be executed, and its variables keep their value - including state-variables in clocked discretized continuous-time equations.
+When a state is suspended its equations should not be executed, and its variables keep their value -- including state-variables in clocked discretized continuous-time equations.
 
 The execution of a sub-state machine has to be suspended when its
 enclosing state is not active. This activation flag is given as a