Generate coverage from doctests

[CathalMullan]

nextest doesn't support doctests at all yet.

[codspeed-hq[bot]]

CodSpeed Performance Report

Merging #134 will not alter performance

_{Comparing 133-generate-coverage-reports-from-doctests (cc0770d) with main (0091571)}

Summary

✅ 16 untouched benchmarks

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

see 11 files with indirect coverage changes