advertise the 2024-08-23_popular-4-shell teaser dataset

2024-08-23_popular-4-shell is a teaser dataset missing from https://docs.softwareheritage.org/devel/swh-export/graph/dataset.html#summary-of-dataset-versions , but is super-interesting for testing purposes due to its small size (the compressed/ dir is just ~65 MiB).

It can be found on S3 at s3://softwareheritage/graph/2024-08-23_popular-4-shell/.

Please advertise it on the web page.

There is also its companion 2024-08-23_popular-10-shell, which might be interesting to advertise too, but currently doesn't have a compressed representation published on S3, so it's less interesting (at least for me g).