[Largest Series Product] Synchronize Addendum Example Code with Tests

[MatthijsBlom]

This patch assumes that the intent of this instructions.append.md was to match the actual requirements.

[github-actions]

Hello. Thanks for opening a PR on Exercism. We are currently in a phase of our journey where we have paused community contributions to allow us to take a breather and redesign our community model. You can learn more in this blog post. As such, all issues and PRs in this repository are being automatically closed.

That doesn't mean we're not interested in your ideas, or that if you're stuck on something we don't want to help. The best place to discuss things is with our community on the Exercism Community Forum. You can use this link to copy this into a new topic there.

---

Note: If this PR has been pre-approved, please link back to this PR on the forum thread and a maintainer or staff member will reopen it.

[BethanyG]

Leaving a note here: exercism/problem-specifications#2246 is discussing the removal of the tests. Once it is PR'd to the tracks, this PR will need to be adjusted/amended.

We'll need to adjust the JinJa2 template, regenerate the test files, and then re-edit this addendum accordingly.

Meanwhile, I am going to put this on hold until the upstream changes are completed.

Edited to add: The upstream changes have been merged, and Katrina will be PR-ing track changes next week, so we should revisit this then.

[BethanyG]

Alrighty. Now that we have things sorted with the intro and which tests are included, we can merge this! Thank you for submitting it. 😄