Consider adding script to spell check jupyter notebooks

> I was also thinking about whether we want a second script for checking jupyter notebooks.

File an issue for it! One idea I had was to export the notebook as markdown using `nbconvert` and then spell check that? It will be a bit harder to go through the output for fixes as line numbers will be wrong, but should still be doable.

_Originally posted by @jashapiro in https://github.com/AlexsLemonade/spellcheck/issues/2#issuecomment-1983824167_

Start by reviewing the repository's existing spelling workflow and the proposed Jupyter notebook approach using nbconvert. Determine how exported Markdown would be spell checked and how fixes can be reported despite changed line numbers; done means a script can check notebook text reliably.

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