Fix: Link casing

Author: michicc

_posts/2025-12-08-openttd-15-0-rc1.md

@@ -1,5 +1,5 @@
 ---
-title: OpenTTD 15.0-rc1
+title: OpenTTD 15.0-RC1
 author: michi_cc
 ---
 
@@ -24,5 +24,5 @@ Some notable changes over the previous beta3 release are:
 As always, see the changelog for the full list.
 
 * [Download](https://www.openttd.org/downloads/openttd-releases/testing.html)
-* [Changelog](https://cdn.openttd.org/openttd-releases/15.0-rc1/changelog.md)
+* [Changelog](https://cdn.openttd.org/openttd-releases/15.0-RC1/changelog.md)
 * [Bug tracker](https://github.com/OpenTTD/OpenTTD/issues)