Remove \textbf on 'active' where it is neither introduced nor deservi…

…ng emphasis

This instance of 'active' doesn't seem to differ in any significant way from the other nearby uses of 'active' that have no special formatting.

chapters/synchronous.tex

@@ -232,7 +232,7 @@ \subsection{Clocks and Clocked Variables}\doublelabel{clocks-and-clocked-variabl
 base type \lstinline!Real!, \lstinline!Integer!, \lstinline!Boolean!, enumeration, \lstinline!String! that are
 associated uniquely with a clock \lstinline[mathescape=true]!c($t_{i}$)!. A
 clocked variable can only be directly accessed at the event instant
-where the associated clock is \textbf{active}. A constant and a
+where the associated clock is active. A constant and a
 parameter can always be used at a place where a clocked variable is
 required.