Update chapters/synchronous.tex

Co-authored-by: Elena Shmoylova <eshmoylova@users.noreply.github.com>

chapters/synchronous.tex

@@ -544,7 +544,7 @@ \section{Clocked State Variables}\label{clocked-state-variables}
 \end{lstlisting}\end{synopsis}
 \begin{semantics}
 The input argument $u$ is a component expression (\cref{def:component-expression}).
-If $u$ is a parameter its value is returned.
+If $u$ is a parameter, its value is returned.
 
 Otherwise:
 Input and return arguments are on the same clock.