Don't say that comments are set in italics

Comments set in italics are now formatted as non-normative content.  The few remaining comments that are not formatted as non-normative content have no special formatting at all.

chapters/introduction.tex

@@ -93,7 +93,7 @@ \section{Some Definitions}\doublelabel{some-definitions}
 
 The semantic specification should be read together with the Modelica
 grammar. Non-normative text, i.e., examples and comments, are enclosed
-  in {[} {]}; comments are set in italics. Additional terms are explained
+in {[}\ldots{]} and set in italics. Additional terms are explained
 in the glossary in \autoref{glossary}. Some important terms are:
 \begin{tabular}{|l|p{10cm}|}
 \hline