listings: use texcl=true to use LaTeX in comments

my-listings.sty

@@ -145,7 +145,8 @@
                   {\lstset{mathescape=true,language=ADT,#1}}
                   {}
 
-\lstset{extendedchars=true, basicstyle=\ttfamily, commentstyle=\itshape, showstringspaces=false}
+\lstset{extendedchars=true, basicstyle=\ttfamily,
+  commentstyle=\itshape, texcl=true, showstringspaces=false}
 
 \newcommand{\lstusecolors}{
 \lstset{backgroundcolor=\color{gray!10}}