P3836R2 Make optional<T&> trivially copyable

Fixes NB US 134-215 (C++26 CD).

Author: eisenwave

source/utilities.tex

@@ -4543,6 +4543,9 @@
 the \defnx{contained value}{contained value!\idxcode{optional.ref}}
 is a reference to \tcode{*\exposid{val}}.
 
+\pnum
+Each type \tcode{optional<T\&>} is a trivially copyable class\iref{class.prop}.
+
 \rSec3[optional.ref.ctor]{Constructors}
 
 \begin{itemdecl}