[class.union.anon] Turn redundant wording into a note

Author: sdkrystian

source/classes.tex

@@ -3323,6 +3323,7 @@
 member functions.
 
 \pnum
+\begin{note}
 A union for which objects, pointers, or references are declared is not an anonymous union.
 \begin{example}
 \begin{codeblock}
@@ -3337,6 +3338,7 @@
 is not visible outside the union, and even if it were visible, it is not
 associated with any particular object.
 \end{example}
+\end{note}
 \begin{note}
 Initialization of unions with no user-declared constructors is described
 in~\ref{dcl.init.aggr}.