docs: Use correct heading in 25.11 release notes

Author: Techassi

modules/ROOT/partials/release-notes/release-25.11.adoc

@@ -773,7 +773,7 @@ These Kubernetes versions are no longer supported:
 
 * `1.30`
 
-==== OpenShift
+===== OpenShift
 
 This release is available in the RedHat Certified Operator Catalog for the following OpenShift versions: