[ML] Update documentation for remote cluster client role in MlPutDatafeedRequest (#3645) (#3921)

* Update documentation for remote cluster client role in MlPutDatafeedRequest

* Refactor comment formatting in MlPutDatafeedRequest for clarity

* Update description for indices in schema.json to clarify remote cluster client role requirements

* pretty

---------

Co-authored-by: István Zoltán Szabó <[email protected]>
Co-authored-by: Quentin Pradet <[email protected]>
(cherry picked from commit c287d34)

Co-authored-by: Valeriy Khakhutskyy <[email protected]>

Author: github-actions[bot]

output/schema/schema.json

@@ -119,8 +119,8 @@ export interface Request extends RequestBase {
      */
     frequency?: Duration
     /**
-     * An array of index names. Wildcards are supported. If any of the indices are in remote clusters, the machine
-     * learning nodes must have the `remote_cluster_client` role.
+     * An array of index names. Wildcards are supported. If any of the indices are in remote clusters, the master
+     * nodes and the machine learning nodes must have the `remote_cluster_client` role.
      * @aliases indexes
      * */
     indices?: Indices