feat(contains): create exercise

[nik-rev]

Because

It was decided to add new recursion exercises

Previous

This PR

• Adds exercise 14

Issue

Related to #27265

Additional Information

Pull Request Requirements

• [x] I have thoroughly read and understand The Odin Project Contributing Guide
• [x] The title of this PR follows the location of change: brief description of change format, e.g. 01_helloWorld: Update test cases
• [x] The Because section summarizes the reason for this PR
• [x] The This PR section has a bullet point list describing the changes in this PR
• [x] If this PR addresses an open issue, it is linked in the Issue section
• [x] If this PR includes any changes that affect the solution of an exercise, I've also updated the solution in the /solutions folder

[mao-sz]

@nikitarevenco to make things easier to know when to do things, once you've made any requested changes etc., if you could re-request a review from whichever maintainer, that would make it much easier to know when it's okay to review (so we don't go to review and submit comments right before you push another commit that changes things again)

[nik-rev]

@nikitarevenco to make things easier to know when to do things, once you've made any requested changes etc., if you could re-request a review from whichever maintainer, that would make it much easier to know when it's okay to review (so we don't go to review and submit comments right before you push another commit that changes things again)

Alright, that makes sense!

[nik-rev]

@nikitarevenco to make things easier to know when to do things, once you've made any requested changes etc., if you could re-request a review from whichever maintainer, that would make it much easier to know when it's okay to review (so we don't go to review and submit comments right before you push another commit that changes things again)

I've opened the next exercise for review! I wanted to 'request' - but seems like that cannot be done on a PR with no reviews yet. For the future, do you prefer me to add a comment when the next PR is ready for review or?

[mao-sz]

@nikitarevenco No need to comment or request a review when un-drafting something. The un-drafting itself is enough to signify that something is ready for review.

I'm not reviewing these because I'm assigned them, nor am I the only one allowed to review them. I just happen to be seeing these and choosing to add my reviews. Any of the maintainers may wish to review (or not) at any time, and it wouldn't be unrealistic if they had different opinions to me or comments on things I hadn't considered. And I'd probably be wanting at least another opinion before they're all finalised for merging.