[DOC] Combined Fields (BM25F) Documentation

[macohen]

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 and all versions that are affected.
We are adding BM25F support which is a new query type we are integrating from Lucene.

What other resources are available? Provide links to related issues, POCs, steps for testing, etc.
opensearch-project/OpenSearch#3996

cc: @mingshl

[kolchfa-aws]

Removing the 2.12 label because this is not going to make it into 2.12 cc: @ylwu-amzn @mingshl

[hdhalter]

@ylwu-amzn , @mingshl , is this going out in 2.13? Thanks.

[mingshl]

@hdhalter thanks for following up. No, we have other priorities for 2.13 now. Will update again once we have new timeline.

[hdhalter]

Hi @mingshl , do you know if this is targeting 2.14? Thanks!

[mingshl]

@hdhalter we are not prioritizing this task, I will close it for now, and reopen this task when we need it. thanks!