[DOC] Add documentation for inner hits within collapse parameter for hybrid query

[ryanbogan]

What do you want to do?

• Request a change to existing documentation
• Add new documentation
• Report a technical problem with the documentation
• Other

Tell us about your request. Provide a summary of the request.
We just enabled inner hits compatibility within the collapse parameter for hybrid query. We need to add the documentation for this feature.
Version: List the OpenSearch version to which this issue applies, e.g. 2.14, 2.12--2.14, or all.
3.2
What other resources are available? Provide links to related issues, POCs, steps for testing, etc.
opensearch-project/neural-search#1379

[opensearch-ci-bot]

Hi @ryanbogan
,

As part of the entrance criteria, all the documentation pull requests need to be drafted and in technical review.

Since there is no pull request linked to this issue, please take one of the following actions:

• Create the pull request and link it to this issue.
  
• If you already have a pull request created, please link it to this issue.
  
• If this feature is not targeted for the currently labeled release version, please update the issue with the correct release version.
  

Please note: Missing documentation can block the release and cause delays in the overall process.

Thank you!