[libc++][NFC] Move incrementable_traits and indirectly_readable_traits into separate headers.

Differential Revision: https://reviews.llvm.org/D100682

GitOrigin-RevId: e0adf7e06a9e329327db2c5e9809e1cbf2e7208d
diff --git a/include/concepts b/include/concepts
index 7127f28..295733b 100644
--- a/include/concepts
+++ b/include/concepts
@@ -439,6 +439,7 @@
 // [concept.strictweakorder]
 template<class _Rp, class _Tp, class _Up>
 concept strict_weak_order = relation<_Rp, _Tp, _Up>;
+
 #endif //_LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
 
 _LIBCPP_END_NAMESPACE_STD