Add to CHANGELOG

Signed-off-by: Craig Perkins <[email protected]>

Author: cwperks

CHANGELOG.md

@@ -22,6 +22,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Introduce system generated ingest pipeline ([#17817](https://github.com/opensearch-project/OpenSearch/pull/17817)))
 
 ### Changed
+- Create generic DocRequest to better categorize ActionRequests ([#18269](https://github.com/opensearch-project/OpenSearch/pull/18269)))
 
 ### Dependencies
 - Bump `com.google.code.gson:gson` from 2.12.1 to 2.13.0 ([#17923](https://github.com/opensearch-project/OpenSearch/pull/17923))