Project Testing Practice: added examples to caesar cipher test cases

[catbree]

Because

This came from issue #27968, a student found the instructions on caesarCipher unclear and suggested to add examples and clarity to make it easier for others to understand.

This PR

• Added example to test wrapping.
• Added clarification and example to test case preservation.
• Added clarification and example to test punctuation.

Issue

Closes #27968

Additional Information

Pull Request Requirements

• I have thoroughly read and understand The Odin Project curriculum contributing guide
• The title of this PR follows the location of change: brief description of change format, e.g. Intro to HTML and CSS lesson: Fix link text
• The Because section summarizes the reason for this PR
• The This PR section has a bullet point list describing the changes in this PR
• If this PR addresses an open issue, it is linked in the Issue section
• If any lesson files are included in this PR, they have been previewed with the Markdown preview tool to ensure it is formatted correctly
• If any lesson files are included in this PR, they follow the Layout Style Guide

[CouchofTomato]

Hey @catbree

Thanks for making this PR.

There are some linting issues. Some aren't related to your PR so you can take them on if you want but some are. Can you take a look at the details for the failing lint check above and let me know if you need anything clarified.

[catbree]

@CouchofTomato I've fixed the linting issues. Question: Is it possible for me to run the markdown lint checks by myself? I was referencing the list of issues directly on Github and the lines didn't match once I started making edits on the file itself. So I thought I may have been missing something...

[CouchofTomato]

@catbree I haven't looked for a while but the last time I looked running github actions outside of their normal execution context was somewhat painful. I haven't heard it's got any easier but I haven't really gone looking.

Thanks for making those changes.

[MaoShizhong]

@catbree and @CouchofTomato Linting (and fixing) can be done locally very easily by following the instructions in our updated curriculum repo contributing guide.

Make sure your branch is in sync with upstream main to so you've got the latest markdown lint configuration. Once that's done, the instructions there make running the checks and autofixing some of the errors fairly straightforward.

[catbree]

Awesome, thank you @CouchofTomato @MaoShizhong I've learnt alot. :-)