Go translation

Rust translation

• no random tests in ruby
• (some) tests use test_expect

I completed this kata somewhere around 2 years ago. The description at the time was:

Given an array, find the duplicates in that array, and return a new array of those duplicates.

Reading this discussion page, it seems people were complaining that--in a particular language--"If order of the output matters, it should be in the description," so on October 23, 2017 someone added that the order matters to the description. This person did not update every language to enforce that new rule.

IMHO, changing the description was the wrong move. A 7 kyu kata for finding duplicates is fine; finding duplicates and preserving the order of their first duplicated instance is more like a 6. The tests requiring a particular order were bad, and should have been fixed instead of fundamentally changing the meaning of the kata years after its original publication.