[dcl.name] Turn informative wording into note (#3964)

Author: sdkrystian

source/declarations.tex

@@ -2402,8 +2402,11 @@
 \end{example}
 
 \pnum
-A type can also be named (often more easily) by using a
-\tcode{typedef}\iref{dcl.typedef}.
+\begin{note}
+A type can also be named by a \grammarterm{typedef-name},
+which is introduced by a typedef declaration
+or \grammarterm{alias-declaration}\iref{dcl.typedef}.
+\end{note}
 
 \rSec2[dcl.ambig.res]{Ambiguity resolution}%
 \indextext{ambiguity!declaration versus cast}%