Add a line about Notification API (#2121)

Author: NataliaIvakina

modules/ROOT/pages/changes-deprecations-removals.adoc

@@ -532,6 +532,10 @@ Replaced by xref:backup-restore/aggregate.adoc[`neo4j-admin backup aggregate`]
 For more information, see xref:clustering/databases.adoc#s3-seed-provider[Seed from URI].
 
 
+=== Java API
+
+Since Neo4j 5.26, the server-side Notification API and the `getNotifications()` method of the Result Core API are deprecated.
+
 == Changes in Neo4j 2025.x
 
 The section covers changes to Neo4j server functionality across different areas.