[template.bitset.general][vector.bool.pspc] Make subclauses for `reference` nested classes#8661

AlisdairM wants to merge 2 commits intocplusplus:maincplusplus/draft:mainfrom

AlisdairM:create_subclause_for_reference_typesAlisdairM/draft:create_subclause_for_reference_typesCopy head branch name to clipboard