[libcxx][ranges] Add concepts in range.utility.helpers.

There are no changes to public APIs.

Differential Revision: https://reviews.llvm.org/D103493

NOKEYCHECK=True
GitOrigin-RevId: 89599e8b201a85c4555e72580b7137e4cce71c94
diff --git a/include/concepts b/include/concepts
index 6c8f325..0b51f53 100644
--- a/include/concepts
+++ b/include/concepts
@@ -442,6 +442,9 @@
 template<class _Rp, class _Tp, class _Up>
 concept strict_weak_order = relation<_Rp, _Tp, _Up>;
 
+template<class _Tp, class _Up>
+concept __different_from = !same_as<remove_cvref_t<_Tp>, remove_cvref_t<_Up>>;
+
 #endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
 
 _LIBCPP_END_NAMESPACE_STD