Use a new 3.15 section

Author: johnzhou721

Lib/idlelib/News3.txt

@@ -1,12 +1,17 @@
-What's New in IDLE 3.14.0
-(since 3.13.0)
-Released on 2025-10-07
+What's New in IDLE 3.15.0
+(since 3.14.0)
+Released on 2026-10-01
 =========================
 
-
 gh-134873: Minor code modernization in extension loader.
 Patch by johnzhou721, Zachary Ware, and Terry J. Reedy.
 
+
+What's New in IDLE 3.14.0
+(since 3.13.0)
+Released on 2025-10-07
+=========================
+
 gh-112936: IDLE - Include Shell menu in single-process mode,
 though with Restart Shell and View Last Restart disabled.
 Patch by Zhikang Yan.