revert URL changes

Author: sarahhaggarty

data/releases.yml

@@ -2,4 +2,4 @@ url: https://github.com/JetBrains/kotlin/releases
 
 latest:
   version: 2.3.0
-  url: https://kotlinlang.org/docs/whatsnew.html
+  url: https://github.com/JetBrains/kotlin/releases/tag/v2.3.0

docs/v.list

@@ -8,7 +8,7 @@
     <var name="kotlinVersion" value="2.3.0"/>
     <var name="kotlinReleaseDate" value="December 16, 2025"/>
     <var name="kotlinLatestUrl" value="https://kotlinlang.org/docs/whatsnew.html"/>
-    <var name="kotlinLatestWhatsnew" value="whatsnew23.md"/>
+    <var name="kotlinLatestWhatsnew" value="https://github.com/JetBrains/kotlin/releases/tag/v2.3.0"/>
 
     <var name="languageVersion" value="2.3"/>
     <var name="apiVersion" value="2.3"/>