[libcxx][ranges] Add `indirectly_movable` and `indirectly_movable_storable`.

Differential Revision: https://reviews.llvm.org/D102639

NOKEYCHECK=True
GitOrigin-RevId: 075f2370c7fa5495649d09be8b1a9802b17a7f2b
diff --git a/include/iterator b/include/iterator
index 08faf4d..929cc16 100644
--- a/include/iterator
+++ b/include/iterator
@@ -125,6 +125,13 @@
 template<weakly_incrementable I, indirectly_regular_unary_invocable<I> Proj>
   struct incrementable_traits<projected<I, Proj>>;         // since C++20
 
+// [alg.req.ind.move], concept indirectly_movable
+template<class In, class Out>
+  concept indirectly_movable = see below;                  // since C++20
+
+template<class In, class Out>
+  concept indirectly_movable_storable = see below;         // since C++20
+
 template<class Category, class T, class Distance = ptrdiff_t,
          class Pointer = T*, class Reference = T&>
 struct iterator                                            // deprecated in C++17