Issue #13883: Document all platforms PYTHONCASEOK works on.
diff --git a/Misc/NEWS b/Misc/NEWS
index 5613ea5..188a09d 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -498,6 +498,8 @@
 Documentation
 -------------
 
+- Issue #13883: PYTHONCASEOK also works on OS X, OS/2, and RiscOS.
+
 - Issue #2134: The tokenize documentation has been clarified to explain why
   all operator and delimiter tokens are treated as token.OP tokens.