[DOC] Updating the K-NN Filters documentation due to recent enhancements in Efficient Filters

[navneet1v]

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.
With the recent improvements in the Efficient Filters in K-NN, we want to update the documentation of Filters in K-NN. The changes include:

1. Support for Efficient Filters in Faiss IVF and IVF PQ algorithms.
2. Update in the logic to switch to exact search in Faiss Filtered Search for Restrictive Filters usecase.
3. Addition of new setting to make the switch to exact search customer driven.

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

1. [Feature] Enhancing Efficient Filters(in Faiss Engine) for Restrictive Filtering use case k-NN#1049
2. [BUG] Empty result set for k-NN search with prefiltering, on faiss index with PQ k-NN#1057