[Transform] Specify use_point_in_time in settings (#5322) (#5464)

use_point_in_time has been in the docs since before 8.18

Resolve elastic/elasticsearch#134841

(cherry picked from commit 9fe24d1)

# Conflicts:
#	specification/_doc_ids/table.csv

Co-authored-by: Pat Whelan <[email protected]>

Author: pquentin

output/openapi/elasticsearch-openapi.json

@@ -499,7 +499,7 @@ painless-contexts,https://www.elastic.co/guide/en/elasticsearch/painless/{branch
 painless-execute-api,https://www.elastic.co/guide/en/elasticsearch/painless/{branch}/painless-execute-api.html,,
 pipeline-processor,https://www.elastic.co/guide/en/elasticsearch/reference/{branch}/pipeline-processor.html,,
 pki-realm,https://www.elastic.co/guide/en/elasticsearch/reference/{branch}/pki-realm.html,,
-point-in-time-api,https://www.elastic.co/guide/en/elasticsearch/reference/{branch}/point-in-time-api.html,,
+point-in-time-api,https://www.elastic.co/guide/en/elasticsearch/reference/{branch}/point-in-time-api.html,,Open a point in time API
 prevalidate-node-removal,https://www.elastic.co/guide/en/elasticsearch/reference/{branch}/prevalidate-node-removal-api.html,,
 preview-dfanalytics,https://www.elastic.co/guide/en/elasticsearch/reference/{branch}/preview-dfanalytics.html,,
 preview-transform,https://www.elastic.co/guide/en/elasticsearch/reference/{branch}/preview-transform.html,,

output/openapi/elasticsearch-serverless-openapi.json

@@ -130,6 +130,16 @@ export class Settings {
    * @server_default 500
    */
   max_page_search_size?: integer
+  /**
+   * Specifies whether the transform checkpoint will use the Point In Time API while searching over the source index.
+   * In general, Point In Time is an optimization that will reduce pressure on the source index by reducing the amount
+   * of refreshes and merges, but it can be expensive if a large number of Point In Times are opened and closed for a
+   * given index. The benefits and impact depend on the data being searched, the ingest rate into the source index, and
+   * the amount of other consumers searching the same source index.
+   * @ext_doc_id point-in-time-api
+   * @server_default true
+   */
+  use_point_in_time?: boolean
 
   /**
    * If `true`, the transform runs in unattended mode. In unattended mode, the transform retries indefinitely in case