docs: Update OpenShift release notes (#817)

Author: razvan

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

@@ -773,19 +773,20 @@ These Kubernetes versions are no longer supported:
 
 * `1.30`
 
-===== OpenShift versions
+==== OpenShift
 
 This release is available in the RedHat Certified Operator Catalog for the following OpenShift versions:
 
 * `4.20`
 * `4.19`
 * `4.18`
-
-These OpenShift versions are no longer supported:
-
 * `4.17`
 * `4.16`
 
+This release changes the memory requests for operators installed from the OpenShift Certified Operator Catalog.
+Previously most operators requested `128Mi` of memory.
+Starting with this release the memory requests have been increased to `256Mi` to improve stability on large clusters.
+
 [WARNING]
 ====
 There is a known issue when updating the certified Stackable Listener Operator on OpenShift clusters `4.18` from version `25.7.0` to `25.11.0`.