Update release notes for Compat, SmartPtr

Author: pdimov

release-notes/boost_1_90_0.adoc

@@ -53,7 +53,6 @@ particularly for mixed successful/unsuccessful queries.
 
 * boost_phrase:library[Compat,/libs/compat/]:
 ** Added `to_underlying.hpp` (contributed by Braden Ganetsky.)
-** Extracted `nontype_t` to its own public header `nontype.hpp` and added `nontype`.
 
 * boost_phrase:library[Container,/libs/container/]:
 ** Reimplemented `deque`. The original implementation was based on
@@ -266,7 +265,6 @@ particularly for mixed successful/unsuccessful queries.
    been marked deprecated and will be removed in a future release.
 ** Configurations that define `BOOST_NO_CXX11_HDR_ATOMIC` are no
    longer supported; a conforming {cpp}11 `<atomic>` is now required.
-** Consequently, Clang 3.5 and 3.6 are no longer supported.
 ** The deprecated macros `BOOST_AC_USE_SPINLOCK`, `BOOST_AC_USE_PTHREADS`,
    `BOOST_SP_USE_SPINLOCK`, and `BOOST_SP_USE_PTHREADS` are no longer
    functional.