Add semantic reranking notebook

[demjened]

Add notebook on semantic reranking (BM25 search + reranking with Cohere through inference endpoint).

[gitnotebooks[bot]]

Found 1 changed notebook. Review the changes at https://gitnotebooks.com/elastic/elasticsearch-labs/pull/308

[leemthompo]

Looks good. We already have a Cohere notebook that includes reranking instructions. Consider a sentence or two in the introduction to mention we have a full-blown Cohere notebook, and potentially mention how the retriever syntax is the differentiator in the notebook added in this PR.

[demjened]

@leemthompo With regards to mentioning the other Cohere notebook, how about this text?

This example will show how to combine search and semantic reranking to improve the accuracy of your search results. We'll be using the rerank feature from Cohere.

Note: for a complete integration with Cohere please refer to this notebook. This example focuses on Cohere reranking only through an Elastic retriever query.

[leemthompo]

Sounds good. Maybe rename the notebook to semantic-reranking-retrievers-cohere.ipynb because we'll be adding at least one more semantic reranking with retrievers notebook using different providers/Eland option.