better plots

• new scripts/plot.nu with common tools and options
• better sets of parameters
• better commands in benches/README.md

added 21 commits

• c9f4b174 - 1 commit from branch main
• c9f4b174...5e6dc412 - 10 earlier commits
• 487f930c - refactor in `plot.nu`
• 1a7efebe - add combined graph with "naive" and "true"
• d7f9af68 - measure more input sizes
• fa7927b2 - split legend in half
• eab3eb7a - sort by x in case benchmarks have been completed out of order
• bb53fe17 - add -y to `plot into-axis-options`
• 4c3f92b4 - add "ratio" plot
• 32b70589 - measure inbreeding when recoding only 1 shard
• 0dd88d83 - fix labels for inbreeding plot
• ef0aaa4b - plot inbreeding from t=0

Compare with previous version

changed the description

enabled an automatic merge when the pipeline for ef0aaa4b succeeds

merged

mentioned in commit 9c3cd0a7