[OpenAPI] Edit mget, multi term vectors, and terms enum APIs (#3052)

Author: lcawl

docs/overlays/elasticsearch-shared-overlays.yaml

@@ -54,15 +54,7 @@ actions:
           x-displayName: Document
           externalDocs:
             description: Reading and writing documents
-            url: https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-replication.html
-        - name: mget
-          x-displayName: Document - Multi get
-        - name: mtermvectors
-          x-displayName: Document - Multi term vectors
-        - name: delete_by_query_rethrottle
-          x-displayName: Document - Rethrottle delete by query
-        - name: update_by_query_rethrottle
-          x-displayName: Document - Rethrottle update by query
+            url: https://www.elastic.co/guide/en/elasticsearch/reference/master/docs-replication.html
       # E  
         - name: enrich
           x-displayName: Enrich