Sample code for the article on syntactic sugar

[lpozo]

Where to put new files:

• New files should go into a top-level subfolder, named after the article slug. For example: my-awesome-article

How to merge your changes:

1. Make sure the CI code style tests all pass (+ run the automatic code formatter if necessary).
2. Find an RP Team member on Slack and ask them to review & approve your PR.
3. Once the PR has one positive ("approved") review, GitHub lets you merge the PR.
4. 🎉

[gahjelle]

@lpozo This looks good! I went ahead and did a few edits directly on the PR: 61d4786

Mostly, I added a bit more output when running the files as scripts. I also included the original walrus version of the user_input and the +/format() version of the debit/credit example