Remove redundant reference to enumeration item

The "the last item" has no added value and just makes the reference overly verbose in the presence of the "item 5" output of \cref.

chapters/connectors.tex

@@ -618,7 +618,7 @@ \section{Restrictions of Connections and Connectors}\label{restrictions-of-conne
   connector that is not part of an expandable connector. \label{enum:exc-conn-case}
 \end{enumerate}
 \begin{nonnormative}
-I.e., a connection set must -- unless the model or block is partial -- contain one source of a signal (the last item (\cref{enum:exc-conn-case})
+I.e., a connection set must --- unless the model or block is partial --- contain one source of a signal (\cref{enum:exc-conn-case}
 covers the case where a connector of a component is left unconnected and the source given textually).
 \end{nonnormative}
 \item