template<class charT, class traits>
constexpr bool operator==(basic_string_view<charT, traits> lhs,
type_identity_t<basic_string_view<charT, traits>> rhs) noexcept;
template<class charT, class traits>
constexpr see below operator<=>(basic_string_view<charT, traits> lhs,
type_identity_t<basic_string_view<charT, traits>> rhs) noexcept;