docs: document array type support

[flying-sheep]

• Closes Document dask support for highly variable genes #3892
• Tests included or not required because:

• Release notes not necessary because:

I double-checked everything in #2578 and mostly winged it for the rest.

Would be nice if one of you could take a look if I mis-specified something.

• I didn’t check if some flavors of highly_variable_genes supports only CSR. Any idea?
• I tried to document things that implicitly convert to csr as “not supporting csc”, except when that’s conditional (i.e sc.pp.scale supports CSC if you don’t specify mask_obs, so that’s detailed in mask_obs).

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 76.90%. Comparing base (508f857) to head (153929c).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3895      +/-   ##
==========================================
+ Coverage   76.82%   76.90%   +0.07%     
==========================================
  Files         116      117       +1     
  Lines       12398    12440      +42     
==========================================
+ Hits         9525     9567      +42     
  Misses       2873     2873              

Flag	Coverage Δ
hatch-test.pre	76.90% <100.00%> (+0.07%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
src/scanpy/_utils/_docs.py	100.00% <100.00%> (ø)
...c/scanpy/experimental/pp/_highly_variable_genes.py	18.44% <ø> (ø)
src/scanpy/get/_aggregated.py	92.78% <ø> (ø)
src/scanpy/neighbors/__init__.py	80.05% <ø> (ø)
src/scanpy/preprocessing/_combat.py	88.46% <ø> (ø)
src/scanpy/preprocessing/_highly_variable_genes.py	94.71% <ø> (ø)
src/scanpy/preprocessing/_normalization.py	94.66% <ø> (ø)
src/scanpy/preprocessing/_pca/__init__.py	90.65% <ø> (ø)
src/scanpy/preprocessing/_qc.py	95.83% <ø> (ø)
src/scanpy/preprocessing/_scale.py	91.20% <ø> (ø)
... and 15 more