Update CHANGES for #280.

Organize them a bit better as well.

CHANGES.rst

@@ -5,6 +5,9 @@
 2.0.0 (unreleased)
 ==================
 
+Platforms
+---------
+
 - Add experimental, untested support for 64-bit Windows on ARM using
   MSVC. See `PR 271 <https://github.com/python-greenlet/greenlet/pull/271>`_.
 
@@ -15,6 +18,19 @@
   older GCC, clang and SunStudio we use ``__thread``, while for older
   MSVC we use ``__declspec(thread)``.
 
+- Wheels compatible with the musllinux specification are built,
+  tested, and uploaded to PyPI. (This was retroactively done for
+  version 1.1.2 as well.)
+
+- This version of greenlet is known to compile and pass tests on
+  CPython 3.11.0a4. Earlier or later 3.11 releases may or may not
+  work. See `PR 280
+  <https://github.com/python-greenlet/greenlet/pull/280>`_. Special
+  thanks to Brandt Bucher and the CPython developers.
+
+Fixes
+-----
+
 - Fix several leaks that could occur when using greenlets from
   multiple threads. For example, it is no longer necessary to call
   ``getcurrent()`` before exiting a thread to allow its main greenlet
@@ -29,15 +45,20 @@
   SEH on 32-bit windows, or if you embed Python in a C++ application.
   Please contact the maintainers if you have problems in this area.
 
+  In general, C++ exception handling is expected to be better on most
+  platforms. This work is ongoing.
+
+Changes
+-------
+
 - The repr of some greenlets has changed. In particular, if the
   greenlet object was running in a thread that has exited, the repr
-  now indicates that.
+  now indicates that. *NOTE:* The repr of a greenlet is not part of
+  the API and should not be relied upon by production code. It is
+  likely to differ in other implementations such as PyPy.
 
 - Main greenlets from threads that have exited are now marked as dead.
 
-- Wheels compatible with the musllinux specification are built,
-  tested, and uploaded to PyPI. (This was retroactively done for
-  version 1.1.2 as well.)
 
 1.1.2 (2021-09-29)
 ==================