Be more vague about appearance of Modelica keywords in listings

chapters/introduction.tex

@@ -103,7 +103,7 @@ \section{Notation and Grammar}\label{notation-and-grammar}
 
 The meta symbols (of the extended BNF-grammar) are defined in~\cref{lexical-conventions}.
 
-Boldface denotes keywords of the Modelica language.
+In Modelica code listings, keywords are highlighted with color and may come in both normal weight and boldface, for example, \lstinline!connect! and \lstinline!equation!.
 Keywords are reserved words and shall not be used as identifiers, with the exception of \lstinline!initial! which is a keyword in section headings, and \lstinline!der! which is a keyword for declaration functions, but it is also possible to call the functions \lstinline!initial! and \lstinline!der!.
 
 See \cref{modelica-concrete-syntax} for a full lexical specification and grammar.