Update changelog.

CHANGES.rst

@@ -12,11 +12,25 @@ Bugs fixed
   C code if the module that imported from them does not use memory views.
   Patch by David Woods.  (Github issue #1415)
 
+* Several declarations in ``libcpp.string`` were added and corrected.
+  Patch by Janek Bevendorff.  (Github issue #4268)
+
+* Pickling unbound Cython compiled methods failed.
+  Patch by Pierre Glaser.  (Github issue #2972)
+
+* The tracing code was adapted to work with CPython 3.10.
+
 * The optimised ``in`` operator failed on unicode strings in Py3.9 and later
   that were constructed from an external ``wchar_t`` source.
   Also, related C compiler warnings about deprecated C-API usage were resolved.
   (Github issue #3925)
 
+* Some compiler crashes were resolved.
+  Patch by David Woods.  (Github issues #4214, #2811)
+
+* An incorrect warning about 'unused' generator expressions was removed.
+  (GIthub issue #1699)
+
 * The attributes ``gen.gi_frame`` and ``coro.cr_frame`` of Cython compiled
   generators and coroutines now return an actual frame object for introspection,
   instead of ``None``.