`<algorithm>`: `ranges::reverse_copy` and `ranges::search` missing `difference_type` casting for `contiguous_iterator` operations

https://github.com/microsoft/STL/blob/04ee87830a404437f1691d6a3e8809e4986d8493/stl/inc/algorithm#L4479

The lhs type is _Out, while the rhs is iter_difference_t<_It>.

https://github.com/microsoft/STL/blob/ef62d3fa0b8e4e2406b9bb74e916e1ca8a1df802/stl/inc/xutility#L5489

The same goes for ranges::search.

#include <algorithm>

int* p;

struct O {
  using iterator_category = std::contiguous_iterator_tag;
  using difference_type = int;
  using element_type = int;
  element_type& operator*() const;
  O& operator++();
  O operator++(int);
  O& operator--();
  O operator--(int);
  O& operator+=(difference_type);
  O& operator-=(difference_type);
  element_type* operator->() const;
  element_type& operator[](difference_type) const;
  friend O operator+(O, difference_type);
  friend O operator+(difference_type, O);
  friend O operator-(O, difference_type);
  friend difference_type operator-(O, O);
  auto operator<=>(const O&) const = default;

  void operator+=(decltype(p - p)) = delete;
};

int main() {
  std::ranges::reverse_copy(p, p, O{});
  std::ranges::search(O{}, O{}, p, p);
}

https://godbolt.org/z/osEE96695

Read the linked operations in stl/inc/algorithm and stl/inc/xutility, focusing on the contiguous_iterator paths for ranges::reverse_copy and ranges::search. Compile the provided reproducer to observe the type mismatch, then check the relevant algorithm tests and add coverage showing both calls work with the custom iterator. Done means the reproducer compiles and the regression tests pass.