[Roman Numerals] Approach docs improvements

[Yrahcaz7]

This PR covers all of the remaining audit items listed in #4289 (see issue 4197 for the original discussion). It also adds a few links to the Python docs where relevant.

However, this PR is still a draft because the recursion approach needs more explanation, and the itertools.starmap() approach would likely benefit from reorganization (these two items were not in the original audit list).

[BethanyG]

@Yrahcaz7 - Thank you so much for this!

However, this PR is still a draft because the recursion approach needs more explanation, and the itertools.starmap() approach would likely benefit from reorganization (these two items were not in the original audit list).

Happy to have you add those two things here, if you'd like. We may as well change whatever needs changing, since we are not likely to not this way again soon. 🙂