Use original PR numbers in 2.8 release notes. (#796) (#798)

* Use original PR numbers in 2.8 release notes.

Signed-off-by: Xuesong Luo <lxuesong@amazon.com>

---------

Signed-off-by: Xuesong Luo <lxuesong@amazon.com>
(cherry picked from commit 104c4b8)

Co-authored-by: Xuesong Luo <lxuesong@amazon.com>

release-notes/opensearch-index-management.release-notes-2.8.0.0.md

@@ -7,11 +7,11 @@ Compatible with OpenSearch 2.8.0
 * Bump version to 2.8. ([#759](https://github.com/opensearch-project/index-management/pull/759))
 
 ### Features
-* Support notification integration with long running operations. ([#790, 791, 793](https://github.com/opensearch-project/index-management/pull/793))
+* Support notification integration with long running operations. ([#712](https://github.com/opensearch-project/index-management/pull/712), [#722](https://github.com/opensearch-project/index-management/pull/722))
 
 ### Bug fixes
-* Remove recursion call when checking permission on indices. ([#785](https://github.com/opensearch-project/index-management/pull/785))
-* Added trimming of nanos part of "epoch_millis" timestamp when date_histogram type used is date_nanos. ([#782](https://github.com/opensearch-project/index-management/pull/782))
+* Remove recursion call when checking permission on indices. ([#779](https://github.com/opensearch-project/index-management/pull/779))
+* Added trimming of nanos part of "epoch_millis" timestamp when date_histogram type used is date_nanos. ([#772](https://github.com/opensearch-project/index-management/pull/772))
 * Added proper resolving of sourceIndex inside RollupInterceptor, it's required for QueryStringQuery parsing. ([#773](https://github.com/opensearch-project/index-management/pull/773))
 
 ### Documentation