mrdocs::Expected<T, E>::and_then

template<class Fn>
requires std::is_constructible_v<E, E&>
constexpr
auto
and_then(Fn&& f) &;

template<class Fn>
requires std::is_constructible_v<E, E const&>
constexpr
auto
and_then(Fn&& f) const &;

template<class Fn>
requires std::is_constructible_v<E, E>
constexpr
auto
and_then(Fn&& f) &&;

template<class Fn>
requires std::is_constructible_v<E, const E>
constexpr
auto
and_then(Fn&& f) const &&;