Example notebook does not render

[wtrTom]

The Learn to rank example notebook linked from the elasticSearch docs does not render

Notebook: https://github.com/elastic/elasticsearch-labs/blob/main/notebooks/search/08-learning-to-rank.ipynb
ElasticSearch dcos: https://www.elastic.co/guide/en/elasticsearch/reference/current/learning-to-rank-model-training.html#learning-to-rank-model-training-workflow

[afoucret]

This is fixed by #462