Add changelog entry

Signed-off-by: Michael Froh <[email protected]>

Author: msfroh

CHANGELOG.md

@@ -86,6 +86,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Skip remote-repositories validations for node-joins when RepositoriesService is not in sync with cluster-state ([#16763](https://github.com/opensearch-project/OpenSearch/pull/16763))
 - Fix _list/shards API failing when closed indices are present ([#16606](https://github.com/opensearch-project/OpenSearch/pull/16606))
 - Fix remote shards balance ([#15335](https://github.com/opensearch-project/OpenSearch/pull/15335))
+- Always use `constant_score` query for `match_only_text` field ([#16964](https://github.com/opensearch-project/OpenSearch/pull/16964))
 
 ### Security