minor updates to upgrade docs (#2470)

Minor issues & leftovers after
#2296

Author: eedugon

deploy-manage/upgrade/deployment-or-cluster/elasticsearch.md

@@ -9,7 +9,7 @@ products:
 
 # Upgrade {{es}} [upgrading-elasticsearch]
 
-An {{es}} cluster can be upgraded one node at a time so upgrading does not interrupt service. Running multiple versions of {{es}} in the same cluster beyond the duration of an upgrade is not supported, as shards cannot be replicated from upgraded nodes to nodes running the older version.
+This document provides the detailed steps for performing a rolling upgrade of a self-managed {{es}} cluster. A rolling upgrade allows you to upgrade your cluster one node at a time without interrupting service. Running multiple versions of {{es}} in the same cluster beyond the duration of an upgrade is not supported, as shards cannot be replicated from upgraded nodes to nodes running the older version.
 
 :::{note}
 Upgrading from a release candidate build, such as 9.0.0-rc1, is unsupported. Use pre-releases only for testing in a temporary environment.

deploy-manage/upgrade/plan-upgrade.md

@@ -151,7 +151,7 @@ The minimum steps your plan should include are:
 1. Upgrade {{es}} and {{kib}} to the latest 8.19 version, as a requirement for the major upgrade to {{version.stack}}.
 2. Upgrade all ingest components to the latest 8.19 version, as otherwise they won't be compatible with {{es}} running {{version.stack}}.
 3. Follow all [preparation steps](./prepare-to-upgrade.md) and use the upgrade assistant to ensure the cluster is ready for a major upgrade.
-4. {{es}} and {{kib}} to {{version.stack}}.
+4. Upgrade {{es}} and {{kib}} to {{version.stack}}.
 
 ## Next steps