Add hybrid search pre-filtering documentation

[RexyZhang2001]

Description

Document the hybrid query common filter as pre-filtering: add a new pre-filtering page, clarify the filter parameter in the hybrid query reference, and cross-link the post-filtering page. The filter must be a single query object; multiple conditions are combined in a bool query.

Issues Resolved

Closes opensearch-project/neural-search#1811

Version

3.0

Frontend features

If you're submitting documentation for an OpenSearch Dashboards feature, add a video that shows how a user will interact with the UI step by step. A voiceover is optional.

Checklist

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[heemin32]

Overall, LGTM. One suggestion: would it make more sense to combine post-filtering.md and pre-filtering.md into a single filtering.md document that covers both pre-filtering and post-filtering? I will leave it to @kolchfa-aws to decide.

[heemin32]

@kolchfa-aws This is for 3.0 and above.

[kolchfa-aws]

@RexyZhang2001 I think it makes sense to keep pre- and post-filtering pages separate. That said, could you add some information so the users can decide when to use pre-filtering and when to use post-filtering? It can go into a parent page (either create a new "Using filtering with hybrid search" parent page and make the pre- and post-filtering children of that page, or just add a section "Filtering data" in the current parent page). That way users can see the difference between the two options right away and we can help them decide which one to use. Thanks!

[RexyZhang2001]

Hi @kolchfa-aws
Thanks for the suggestion! I've added a new section to the current hybrid search parent page with a comparison table that summarizes the differences between pre-filtering and post-filtering. This should help users decide which approach fits their use case before reading both child pages first.

I would really appreciate it if you could take a look at this blog change as well when you get a chance, thanks: opensearch-project/project-website#4169

[kolchfa-aws]

Thanks for the updates, @RexyZhang2001! Doc review complete and changes applied.