explain wha no-c-format

Co-authored-by: Henrik Tidefelt <henrikt@wolfram.com>

chapters/packages.tex

@@ -369,6 +369,8 @@ \section{Multilingual Descriptions}\label{multilingual-descriptions}
 msgstr $\mathit{messageTranslation}$
 \end{lstlisting}
 
+The use of \lstinline!no-c-format! ensures that translation tools will not parse \lstinline!"%class"! as the format specifier \lstinline!%c! followed by \emph{lass}.
+
 \begin{nonnormative}
 In the remainder of this section, several facts about the gettext specification are interleaved non-normatively for easy access to some of the gettext basics.
 Always refer to the external gettext specification for full detail or in case of doubt.