Added new practice exercise: state-of-tic-tac-toe

[AbhilashJN]

Fixes #2170

Can you please let me know where I can find the appropriate values for the practices, prerequisites, difficulty and topics fields?

[github-actions]

Dear AbhilashJN

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[andrerfcsantos]

Awesome work on this one! You even included the test generator, which is great.

For the practices and prerequisites keys, you can leave them as empty arrays. It's something we will fill out when we have a more finalized set of concepts for the track. You can see the related issue here: #1396
For the topics and difficulty keys, see the comments below.

Also left some other suggestions for other things, let me know what you think.

In addition to the comments I left, one thing I considered is whether it would be better to have a State type as a return result instead of a string. The type could be something like this:

type State string

const (
    Win State = "win"
    Draw State = "draw"
    Ongoing State = "ongoing"
)

We could include this in the stub or in a separate file. Let me know what you think about this too.

[andrerfcsantos]

A couple more changes.

After these changes, I'll do another pass over everything, but it's looking really good!

[andrerfcsantos]

🚀