[DOC] Support radius search in k-NN

[junqiu-lei]

What do you want to do?

• [ ] Request a change to existing documentation
• [x] 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 introducing a radius search feature in the k-NN plugin, necessitating updates to the documentation. This update impacts versions starting from 2.13.

The radius search feature enables users to find all points within a specified distance from a query point in a vector space, enhancing search flexibility and utility. This significant enhancement requires documentation updates to accurately reflect the new capabilities available from version 2.13 onwards.

What other resources are available? Provide links to related issues, POCs, steps for testing, etc.

RFC: https://github.com/opensearch-project/k-NN/issues/1483 Issue: https://github.com/opensearch-project/k-NN/issues/814

[hdhalter]

Thanks for entering this issue, @junqiu-lei! Will you be writing the PR for this doc update?

[junqiu-lei]

Hi @hdhalter, yes and this feature moved to 2.14 release.

[hdhalter]

Hi @junqiu-lei , what is your ETA for producing the doc PR? To meet entrance criteria, the PR must be open and in review by 4/30. Thanks!

[junqiu-lei]

Hi @hdhalter I'm working on this doc, will have PR in review before 4/30. Thanks!