Fix typos in documentation and add claude.md

[finsberg]

No description provided.

[codspeed-hq]

Merging this PR will not alter performance

✅ 8 untouched benchmarks

---

_{Comparing improve-docs (4d6cce1) with main (6c6354b)¹}

Footnotes

1. No successful run was found on main (4d6cce1) during the generation of this report, so 6c6354b was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩