Opinionated defaults for 2.0

[flying-sheep]

Some functions can be given defaults that depend on conventions

• layer="counts" for read functions
• mask_var="highly_variable" in RankGenesGroupsPreset?
  • and maybe even PCA?

more?

threads:

• https://theislab-munich.slack.com/archives/C04U6DW20NB/p1774522763964959
• https://scverse.zulipchat.com/#narrow/channel/328272-scanpy/topic/What.20are.20your.20favourite.20defaults.20.2F.20replacements.20for.202.2E0.3F/with/584681746

So far: https://scanpy.readthedocs.io/en/latest/generated/scanpy.Preset.html