Add 2.19 documentation release notes (opensearch-project#9175)

* Add 2.19 documentation release notes

Signed-off-by: Archer <[email protected]>

* make PR titles consistent

Signed-off-by: Archer <[email protected]>

---------

Signed-off-by: Archer <[email protected]>

Author: Naarcha-AWS

release-notes/opensearch-documentation-release-notes-2.19.0.md

@@ -0,0 +1,36 @@
+# OpenSearch Documentation Website 2.19.0 Release Notes
+
+The OpenSearch 2.19.0 documentation includes the following additions and updates.
+
+## New documentation for 2.19.0
+
+- Adds star-tree search changes related to new aggregations supported [#9163](https://github.com/opensearch-project/documentation-website/pull/9163)
+- Adds QueryInsightsDashboard [#9157](https://github.com/opensearch-project/documentation-website/pull/9157)
+- Add Convert Index to remote documentation [#9156](https://github.com/opensearch-project/documentation-website/pull/9156)
+- Adds details for using index_thread_qty for Lucene library [#9152](https://github.com/opensearch-project/documentation-website/pull/9152)
+- Update threshold for 2.19 [#9151](https://github.com/opensearch-project/documentation-website/pull/9151)
+- Add avx512_spr documentation [#9148](https://github.com/opensearch-project/documentation-website/pull/9148)
+- Add documentation for plugin as a service [#9144](https://github.com/opensearch-project/documentation-website/pull/9144)
+- Add AD flatten result index feature [#9140](https://github.com/opensearch-project/documentation-website/pull/9140)
+- Add documentation for `wait_for_completion_timeout` Parameter [#9138](https://github.com/opensearch-project/documentation-website/pull/9138)
+- Add feature direction to AD docs [#9137](https://github.com/opensearch-project/documentation-website/pull/9137)
+- Add verbose_pipeline section in using-search-pipeline [#9130](https://github.com/opensearch-project/documentation-website/pull/9130)
+- Query Insights 2.19 documentation [#9120](https://github.com/opensearch-project/documentation-website/pull/9120)
+- Add template query [#9119](https://github.com/opensearch-project/documentation-website/pull/9119)
+- Add RRF documentation for hybrid search [#9117](https://github.com/opensearch-project/documentation-website/pull/9117)
+- Add Pagination in hybrid query [#9109](https://github.com/opensearch-project/documentation-website/pull/9109)
+- Mark nmslib references for vector search as deprecated [#9107](https://github.com/opensearch-project/documentation-website/pull/9107)
+- Add in-place SSL certs hot reload documentation [#9103](https://github.com/opensearch-project/documentation-website/pull/9103)
+- Add binary Lucene vector updates for 2.19 [#9102](https://github.com/opensearch-project/documentation-website/pull/9102)
+- Add OpenSearch Flow OSD plugin [#9101](https://github.com/opensearch-project/documentation-website/pull/9101)
+- Update hot reload documentation to show how DN validation can be skipped [#9079](https://github.com/opensearch-project/documentation-website/pull/9079)
+- Update k-NN Cosine formula [#9078](https://github.com/opensearch-project/documentation-website/pull/9078)
+= Update Ada Grad as the default optimiser. [#9061](https://github.com/opensearch-project/documentation-website/pull/9061)
+- Add documentation about explain in hybrid query and hybrid_score_explanation processor [#9053](https://github.com/opensearch-project/documentation-website/pull/9053)
+- Add Query Insights local index delete after documentation [#9052](https://github.com/opensearch-project/documentation-website/pull/9052)
+- Add support for Bedrock Rerank API #9027 [#9029](https://github.com/opensearch-project/documentation-website/pull/9029)
+- Add validation requirement for message fields [#9000](https://github.com/opensearch-project/documentation-website/pull/9000)
+- Add documentation for workspace privacy [#8994](https://github.com/opensearch-project/documentation-website/pull/8994)
+- Add documentation for pruning neural sparse vectors [#8984](https://github.com/opensearch-project/documentation-website/pull/8984)
+- Add document the usage of update document API with ingest pipeline [#8874](https://github.com/opensearch-project/documentation-website/pull/8874)
+- Update innerHits of nested k-NN fields [#8822](https://github.com/opensearch-project/documentation-website/pull/8822)