DOC: Fix errors detected by sphinx-lint
Found a few issues on the doc with [sphinx-lint](https://github.com/sphinx-contrib/sphinx-lint).

Fixed them.
Nice, thanks - could you add this to https://github.com/pandas-dev/pandas/blob/672798ec7b5565366be24aa4f57f6374f3a5e0fd/.pre-commit-config.yaml I don't understand the error :( looks unrelated, don't worry about it Should I merge main to get it fixed (in other words, do I have something to do?) I re-ran and it passed - all good, thanks!