Updating release notes with NumTermAgg changes (#18977) (#18980)

(cherry picked from commit ba296fb)

Signed-off-by: Vinay Krishna Pudyodu <[email protected]>
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

Author: opensearch-trigger-bot[bot]

release-notes/opensearch.release-notes-3.2.0.md

@@ -53,6 +53,7 @@ Compatible with OpenSearch and OpenSearch Dashboards version 3.2.0
 * Supporting Scripted Metric Aggregation when reducing aggregations in InternalValueCount and InternalAvg ([18411](https://github.com/opensearch-project/OpenSearch/pull18411)))
 * Support `search_after` numeric queries with Approximation Framework ([#18896](https://github.com/opensearch-project/OpenSearch/pull/18896))
 * Add skip_list parameter to Numeric Field Mappers (default false) ([#18889](https://github.com/opensearch-project/OpenSearch/pull/18889))
+* Optimization in Numeric Terms Aggregation query for Large Bucket Counts([#18702](https://github.com/opensearch-project/OpenSearch/pull/18702))
 
 ### Changed
 * Update Subject interface to use CheckedRunnable ([#18570](https://github.com/opensearch-project/OpenSearch/issues/18570))