More complete dataset documentation

[flying-sheep]

Each dataset’s documentation should contain

1. what it contains (listing obs, …)
2. what steps have been run on it
3. better links (e.g. is pbmc68k_reduced this one? the docstring isn’t clear. It was added by @fidelram in new ranked genes plotting functions #228 …)

Especially important is if its .X is logarithmized, normalized, and/or filtered

See also: https://github.com/orgs/scverse/projects/18/views/1?pane=issue&itemId=62702062

cc @ilan-gold

[flying-sheep]

idea for semi-automating 1.: we could have a representation (ideally the new fancy HTML one) created and attached by CI

[flying-sheep]

I think pbmc68k_reduced was processed something like

sc.pp.normalize_total(adata, target_sum=1e6)
sc.pp.log1p(adata)
sc.pp.scale(adata)

still no idea what’s in “raw” as it’s clearly not counts …