Update chapters/packages.tex

Co-authored-by: Thomas Beutlich <modelica@tbeu.de>

chapters/packages.tex

@@ -354,7 +354,7 @@ \section{Multilingual Descriptions}\label{multilingual-descriptions}
 \item Template file \filename{$\mathit{LibraryName}$.pot}, as the resource \filename{modelica://$\mathit{LibraryName}$/Resources/Language/$\mathit{LibraryName}$.pot}.
 It describes all translatable strings in the library, but does not contain any translations.
 The pattern \filename{$\mathit{LibraryName}$} denotes the toplevel class name of the library.
-\item One file for each supported language with the name \filename{$\mathit{LibraryName}$.$\mathit{language}$.po}, as the resource \filename{modelica://$\mathit{LibraryName}$/Resources/Language/$\mathit{LibraryName}$.$\mathit{language}$.po}.
+\item One file for each supported language with the name \filename{$\mathit{LibraryName}$.$\mathit{language}$.po} (Portable Object), as the resource \filename{modelica://$\mathit{LibraryName}$/Resources/Language/$\mathit{LibraryName}$.$\mathit{language}$.po}.
 This file is a copy of the associated template file, but extended with the translations in the specified language.
 The pattern \filename{$\mathit{language}$} stands for the ISO 639-1 language code, e.g., \filename{de} or \filename{sv}.
 \end{enumerate}