Merge 2025-11 LWG Motion 7

P3836R2 Make `optional<T&>` trivially copyable

Author: tkoeppe

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}