Added CHANGELOG.

Signed-off-by: dblock <[email protected]>

CHANGELOG.md

@@ -132,6 +132,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Introduce new feature flag "WRITEABLE_REMOTE_INDEX" to gate the writeable remote index functionality ([#11717](https://github.com/opensearch-project/OpenSearch/pull/11170))
 - Bump OpenTelemetry from 1.32.0 to 1.34.1 ([#11891](https://github.com/opensearch-project/OpenSearch/pull/11891))
 - Support index level allocation filtering for searchable snapshot index ([#11563](https://github.com/opensearch-project/OpenSearch/pull/11563))
+- Add `org.opensearch.rest.MethodHandlers` and `RestController#getAllHandlers` ([11876](https://github.com/opensearch-project/OpenSearch/pull/11876))
 
 ### Dependencies
 - Bumps jetty version to 9.4.52.v20230823 to fix GMS-2023-1857 ([#9822](https://github.com/opensearch-project/OpenSearch/pull/9822))