Explain hybrid search algorithm

[Strift]

Customers have expressed that it's difficult to understand how filters and ranking rules apply to search results in a hybrid search context.

@macraig asked the question internally, and the discussion showed that it wasn't obvious. Check out the Slack thread.

The PRD explains how the search algorithm works. Should this be in the docs too?

[guimachiavelli]

It took me quite a few reads to sort of understand it, and I'm not sure how much I can simplify it without making it useless. It could be interesting material for users who want to really understand what's going on, though, but I wouldn't want it to be our first line of defence.

If the issue is that users don't understand how to use filters and ranking rules with vector search, I think it's more friendly to try and address that directly with a practical guide.

What do you think? Does that sound reasonable?