Update NEWS and idlelib NEWS.text.

Lib/idlelib/NEWS.txt

+What's New in IDLE 3.5.3?
+=========================
+*Release date: 2017-01-01?*
+
+- Issue #27365: Allow non-ascii chars in IDLE NEWS.txt, for contributor names.
+
+- Issue #27245: IDLE: Cleanly delete custom themes and key bindings.
+  Previously, when IDLE was started from a console or by import, a cascade
+  of warnings was emitted.  Patch by Serhiy Storchaka.
+
+
 What's New in IDLE 3.5.2?
 =========================
-*Release date: 2016-06-30?*
+*Release date: 2016-06-26*
 
 - Issue #5124: Paste with text selected now replaces the selection on X11.
   This matches how paste works on Windows, Mac, most modern Linux apps,

Misc/NEWS

@@ -57,6 +57,15 @@ Library
 
 - Issue #26930: Update Windows builds to use OpenSSL 1.0.2h.
 
+IDLE
+----
+
+- Issue #27365: Allow non-ascii chars in IDLE NEWS.txt, for contributor names.
+
+- Issue #27245: IDLE: Cleanly delete custom themes and key bindings.
+  Previously, when IDLE was started from a console or by import, a cascade
+  of warnings was emitted.  Patch by Serhiy Storchaka.
+
 C API
 -----