[BUG] (docs) ext object in the request body of Search API is not documented

[AlexElin]

Describe the bug

The ext object in the request body of Search API is not documented.

Although there is a description of the ext field in the response body

Related component

No response

To Reproduce

1. Go to https://opensearch.org/docs/latest/api-reference/search/#request-body

Expected behavior

There is a description of the ext field of the request body

Additional Details

Screenshots

Host/Environment (please complete the following information):

• Version 2.19

[jainankitk]

@AlexElin - Thanks for reporting this bug. As per my understanding and documentation here, plugin authors can add an ext object to the search response.

Is there a reason for it to be part of the search request body?

[AlexElin]

@jainankitk, I suppose yes, because the ext in the search request body

• is used in the Retrieval-augmented generation processor
  
• is present in the SearchRequest class in the official OpenSearch Java Client (was added in PR Add missed fields to MultisearchBody: ext, rescore and to SearchRequest: ext opensearch-java#918)