Add description of what a default value in record means.

chapters/annotations.tex

@@ -49,6 +49,7 @@ \section{Documentation}\label{annotations-for-documentation}\label{documentation
 
 \subsection{How to Interpret Annotation Definitions}
 If the annotation itself is described by a \lstinline!record! \emph{class} the annotation can be seen as a modifier for a \lstinline!record! \emph{component} with the same name.
+A default value for a record member will be used if there is no modifier for that record member.
 If the annotation is declared as a parameter the corresponding modifier must be an evaluable parameter.
 If the annotation is declared as a constant the corresponding modifier must be a literal value.