[DOC] Document hybrid query behavior when it's nested inside compound queries like function_score

[martin-gaievski]

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.
Hybrid query documentation should document the behavior when hybrid query is used inside compound queries like bool or function_score query.

Starting from initial release in OpenSearch 2.11 hybrid query cannot be nested inside other queries. In version 3.6 team added a hard stop check that will throw exception for such queries (PR opensearch-project/neural-search#1791).

I suggest we update the hybrid query documentation and add Limitations section that explains all these details.

Version: 2.11+

[kolchfa-aws]

Hi @martin-gaievski, this feature is for 3.6+, correct? Not 2.11+?

[martin-gaievski]

Hi @martin-gaievski, this feature is for 3.6+, correct? Not 2.11+?

So I'm not sure how to put version correctly. Actual logic of hybrid not supporting nested HQ stays from 2.11, and in 3.6 I've added validation with user facing message.

[kolchfa-aws]

Got it. Then it should be backported and I don't think we need to mention 3.6. The main goal is to document what the users shoud/should not do. How the code enforces it can be omitted in the docs.