[libc++] Removes _LIBCPP_AVAILABILITY_TO_CHARS.
After moving the std::to_chars base 10 implementation from the dylib to
the header the integral overloads of std::to_chars are available on all
platforms.
Remove the _LIBCPP_AVAILABILITY_TO_CHARS availability macro and update
the tests.
Depends on D125704
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D125745
NOKEYCHECK=True
GitOrigin-RevId: b968c3452b6a6ccef2545d860c4694dc95dcebc1
diff --git a/docs/ReleaseNotes.rst b/docs/ReleaseNotes.rst
index c2a43a6..c21d1f9 100644
--- a/docs/ReleaseNotes.rst
+++ b/docs/ReleaseNotes.rst
@@ -69,6 +69,10 @@
should include assertions or not by default. For details, see
:ref:`the documentation <assertions-mode>` about this new feature.
+- The implementation of the function ``std::to_chars`` for integral types has
+ moved from the dylib to the header. This means the function no longer has a
+ minimum deployment target.
+
API Changes
-----------