Be explicit about the struct being tagged (#3898)

Author: henrikt-ma

chapters/functions.tex

@@ -2120,7 +2120,7 @@ \subsubsection{Records}\label{records}
 A Modelica record class is mapped as follows:
 \begin{itemize}
 \item
-  The record class is represented by a struct in C.
+  The record class is represented by a tagged struct in C.
   A definition of the struct may be specified using the annotations in \cref{annotations-for-c-mapping-of-records}.
 \item
   Each component of the Modelica record is mapped to its corresponding C representation.