DOCSP-34057 add doc for $vectorSearch pipeline stage (#5503)

* DOCSP-34057 add doc for vectorSearch pipeline stage

* DOCSP-34057 updates for copy feedback

* DOCSP-34057 fix for broken links

* DOCSP-34057 updates for AB's feedback

* DOCSP-34057 updates for AB's feedback

Author: kanchana-mongodb

source/reference/operator/aggregation-pipeline.txt

@@ -116,3 +116,4 @@ For the updates, the pipeline can consist of the following stages:
    /reference/operator/aggregation/unionWith
    /reference/operator/aggregation/unset
    /reference/operator/aggregation/unwind
+   /reference/operator/aggregation/vectorSearch

source/reference/operator/aggregation/vectorSearch.txt

@@ -0,0 +1,32 @@
+===========================
+$vectorSearch (aggregation)
+===========================
+
+.. default-domain:: mongodb
+
+``$vectorSearch`` performs a semantic search on data in your Atlas
+cluster. If you store vector embeddings that are less than or equal to
+2048 dimensions in width for any kind of data along with other data in
+your collection on the Atlas cluster, you can seamlessly index the
+vector data along with your other data. You can then use the
+:pipeline:`$vectorSearch` stage to pre-filter your data and perform
+semantic search against the indexed fields. 
+
+.. important:: 
+
+   The ``$vectorSearch`` aggregation pipeline stage is only available
+   for collections hosted on :atlas:`MongoDB Atlas </>` cluster tiers 
+   running MongoDB version 6.0.11 or later. To learn more, see 
+   :atlas:`Atlas Vector Search
+   </atlas-vector-search/vector-search-overview/>`. 
+
+Learn More 
+----------
+
+- To learn more about creating Atlas Vector Search indexes, see
+  :atlas:`Index Vector Embeddings
+  </atlas-vector-search/vector-search-type/>`. 
+
+- To learn more about :pipeline:`$vectorSearch` pipeline stage syntax
+  and usage, see :atlas:`Vector Search Queries
+  </atlas-vector-search/vector-search-stage/>`.