[libc++][doc] Add a todo.

As suggested in D113831.

diff --git a/libcxx/include/format b/libcxx/include/format
index e1002e7..ce16857 100644 (file)
--- a/libcxx/include/format
+++ b/libcxx/include/format
@@ -313,6 +313,8 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 // to support compilers with partial C++20 support.
 #if !defined(_LIBCPP_HAS_NO_CONCEPTS)
 
+// TODO FMT Move the implementation in this file to its own granular headers.
+
 // TODO FMT Evaluate which templates should be external templates. This
 // improves the efficiency of the header. However since the header is still
 // under heavy development and not all classes are stable it makes no sense