Add binary-search exercise (#297)

[Adrien-LUDWIG]

Related to #297

I put 2 as difficulty, what do you think?

Is the prototype and naming good (i.e. binary-search array value), or should it follow the instruction story (i.e. find-song-index playlist song)?

Do not hesitate to tell me there are things to modify @BNAndras. 😉

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[BNAndras]

I put 2 as difficulty, what do you think?>

Seems fine. The website bins difficulties 1 - 3 as "easy" so the specific level isn't too important. I try to avoid level 1 simply because exercises at the same level should be roughly equivalent in difficulty. hello-world is level 1 so only pretty straightforward exercises should also be level 1 in my opinion.

Is the prototype and naming good (i.e. binary-search array value), or should it follow the instruction story (i.e. find-song-index playlist song)?>

The naming is fine. Typically, I'd go with the property name from the canonical test json if it makes sense (so find array value). If the name can be tweaked to be more idiomatic, I'd do that like when transforming a to b, you'll often see a->b like number->string'. However binary-search` is fine, and other tracks take that approach as well.

[Adrien-LUDWIG]

Ok, thanks!

Well, I think it's ready then. I'll wait for your review and try to work on another in the meantime. 😉

[Adrien-LUDWIG]

Sorry, I didn't see your review on my phone. The formatting issues are resolved.

Do not hesitate to tell me if there's anything else.

[Adrien-LUDWIG]

Done. 😉

[Adrien-LUDWIG]

Oh, and could you please add the hacktoberfest-accepted label? 🙏😄