message: sample algorithm: use `iter_difference_t` instead of the deprecated `difference_type_t`
diff: @@ -48,7 +48,7 @@ namespace ranges
  {
  if(pop_size > 0 && sample_size > 0)
  {
  - std::uniform_int_distribution<difference_type_t<I>> dist;
  + std::uniform_int_distribution<iter_difference_t<I>> dist;
  using param_t = typename decltype(dist)::param_type;
  for(; first != last; ++first)
  {
  @@ -94,7 +94,7 @@ namespace ranges
  // next(out,n) are O(1).
  if(n > 0)
  {
  - for(difference_type_t<O> i = 0; i < n; (void)++i, ++first)
  + for(iter_difference_t<O> i = 0; i < n; (void)++i, ++first)
  {
  if(first == last)
  {
  @@ -104,7 +104,7 @@ namespace ranges
  *next(out, i) = *first;
  }
  - std::uniform_int_distribution<difference_type_t<O>> dist;
  + std::uniform_int_distribution<iter_difference_t<O>> dist;
  using param_t = typename decltype(dist)::param_type;
  for(auto pop_size = n; first != last; (void)++first, ++pop_size)
  {
  @@ -153,7 +153,7 @@ namespace ranges
  }
  template<typename Rng, typename O, typename Gen = detail::default_random_engine &>
  - auto operator()(Rng && rng, O out, difference_type_t<O> const n,
  + auto operator()(Rng && rng, O out, iter_difference_t<O> const n,
  Gen && gen = detail::get_random_engine()) const
  -> CPP_ret(sample_result<safe_iterator_t<Rng>, O>)( //
  requires InputRange<Rng> && WeaklyIncrementable<O> && IndirectlyCopyable<
  