add pr link against the change

Signed-off-by: Kaushal Kumar <[email protected]>

CHANGELOG.md

@@ -54,7 +54,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Change http code on create index API with bad input raising NotXContentException from 500 to 400 ([#4773](https://github.com/opensearch-project/OpenSearch/pull/4773))
 - Improve summary error message for invalid setting updates ([#4792](https://github.com/opensearch-project/OpenSearch/pull/4792))
 - Return 409 Conflict HTTP status instead of 503 on failure to concurrently execute snapshots ([#8986](https://github.com/opensearch-project/OpenSearch/pull/5855))
-- Add task completion count in search backpressure stats API
+- Add task completion count in search backpressure stats API ([#10028](https://github.com/opensearch-project/OpenSearch/pull/10028/))
 - Performance improvement for Datetime field caching ([#4558](https://github.com/opensearch-project/OpenSearch/issues/4558))
 
 ### Deprecated