Include file descriptor error message in changelog

CHANGES.txt

@@ -1,6 +1,14 @@
 3.3.0 (Next 3.x Release)
 ------------------------
 
+- ``supervisord`` will now use ``kqueue``, ``poll``, or ``select`` to monitor
+  its file descriptors, in that order, depending on what is available on the
+  system.  Previous versions used ``select`` only and would crash with the error
+  ``ValueError: filedescriptor out of range in select()`` when running a large
+  number of subprocesses (whatever number resulted in enough file descriptors
+  to exceed the fixed-size file descriptor table used by ``select``, which is
+  typically 1024).  Patch by Igor Sobreira.
+
 - ``/etc/supervisor/supervisord.conf`` has been added to the config file search
   paths.  Many versions of Supervisor packaged for Debian and Ubuntu have
   included a patch that added this path.  This difference was reported in a