Use MultiQueryRetriever to get better results

[arsaboo]

I recently came across MultiQueryRetriever, which does a great job of fine-tuning the prompts and generating multiple queries from different perspectives for a given user input query. Basically, it creates multiple versions of the query, retrieves the results, and then combines them. See here for why we should use this approach and here's an example of this implementation.

In my experience, this approach consistently yields better results. MultiQueryRetriever should be a trivial extension, as we already use the Langchain framework.