Fix #10003. Add SIGBREAK to the set of valid signals on Windows.

This fixes a regression noticed by bzr, introduced by issue #9324.
diff --git a/Misc/NEWS b/Misc/NEWS
index a0d8275..8e99376 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,9 @@
 Core and Builtins
 -----------------
 
+- Issue #10003: Allow handling of SIGBREAK on Windows. Fixes a regression
+  introduced by issue #9324. 
+
 - Issue #9979: Create function PyUnicode_AsWideCharString().
 
 - Issue #7397: Mention that importlib.import_module() is probably what someone