[dcl.pre] Turn 'must' into a note.

Author: jensmaurer

source/declarations.tex

@@ -214,10 +214,15 @@
 
 \pnum
 If the \grammarterm{decl-specifier-seq} contains the \tcode{typedef}
-specifier, the declaration is called a \defnx{typedef declaration}{declaration!typedef},
-each \grammarterm{declarator-id} must be an \grammarterm{identifier}
-and is declared to be a \grammarterm{typedef-name}, synonymous with its
-associated type\iref{dcl.typedef}. If the
+specifier, the declaration is called a \defnx{typedef declaration}{declaration!typedef}
+and each \grammarterm{declarator-id}
+is declared to be a \grammarterm{typedef-name}, synonymous with its
+associated type\iref{dcl.typedef}.
+\begin{note}
+Such a \grammarterm{declarator-id} is an \grammarterm{identifier}
+(\ref{class.conv.fct}).
+\end{note}
+If the
 \grammarterm{decl-specifier-seq} contains no \tcode{typedef} specifier, the
 declaration is called a \defnx{function declaration}{declaration!function} if
 the type associated with a \grammarterm{declarator-id} is a function type\iref{dcl.fct} and