Add changelog entry

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

CHANGELOG.md

@@ -26,6 +26,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Add _list/shards API as paginated alternate to _cat/shards ([#14641](https://github.com/opensearch-project/OpenSearch/pull/14641))
 - Latency and Memory allocation improvements to Multi Term Aggregation queries ([#14993](https://github.com/opensearch-project/OpenSearch/pull/14993))
 - Flat object field use IndexOrDocValuesQuery to optimize query ([#14383](https://github.com/opensearch-project/OpenSearch/issues/14383))
+- [Experimental] Approximate match_all query with sort by range query ([#16321](https://github.com/opensearch-project/OpenSearch/pull/16321))
 
 ### Dependencies
 - Bump `com.azure:azure-identity` from 1.13.0 to 1.13.2 ([#15578](https://github.com/opensearch-project/OpenSearch/pull/15578))
@@ -85,7 +86,6 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - [Streaming Indexing] Fix intermittent 'The bulk request must be terminated by a newline [\n]' failures [#16337](https://github.com/opensearch-project/OpenSearch/pull/16337))
 - Fix wrong default value when setting `index.number_of_routing_shards` to null on index creation ([#16331](https://github.com/opensearch-project/OpenSearch/pull/16331))
 - Fix disk usage exceeds threshold cluster can't spin up issue ([#15258](https://github.com/opensearch-project/OpenSearch/pull/15258)))
-
 - Fix inefficient Stream API call chains ending with count() ([#15386](https://github.com/opensearch-project/OpenSearch/pull/15386))
 
 ### Security