[libcxx] adds __cpp_lib_concepts feature-test macro
Also adjusts C++20 status paper to indicate full concepts support.
Depends on D96477, D99817.
Differential Revision: https://reviews.llvm.org/D99805
GitOrigin-RevId: 920c0f7e09e2a55a800a181fb9bfe296a8733c89
diff --git a/docs/FeatureTestMacroTable.rst b/docs/FeatureTestMacroTable.rst
index 806b30f..8c4f2a8 100644
--- a/docs/FeatureTestMacroTable.rst
+++ b/docs/FeatureTestMacroTable.rst
@@ -198,7 +198,7 @@
------------------------------------------------- -----------------
``__cpp_lib_char8_t`` ``201811L``
------------------------------------------------- -----------------
- ``__cpp_lib_concepts`` *unimplemented*
+ ``__cpp_lib_concepts`` ``202002L``
------------------------------------------------- -----------------
``__cpp_lib_constexpr_algorithms`` ``201806L``
------------------------------------------------- -----------------