feat(doctest): expand doctests

[royveshovda]

Update doctests to include example string first.

Might be only my personal flow. I usually start with the example string, before I tackle the main input

[mathsaey]

That is a good catch; the generated doctests should have called example_string from the get go, but it seems I messed up.

I did make two changes though:

1. I also updated the cheatsheet, as it also showed the wrong function call.
2. I removed the extra comments you've added, as I don't think they're needed. If no result is provided, the doctest will accept anything (so it won't cause errors; right now it does due to the call to example_input).

Let me know if this is okay to you and I will push a new version to hex later today!

[royveshovda]

Looks all good to me. Thanks for a very useful set of tools, btw.