Genuinely asking, what would the solution look like in idiomatic Go?
Let's assume for a second that the premise of the article is valid and exactly the behavior we want - "asynchronous execution but to report the results in order, as each becomes available".
Slightly more complicated than that, because you can only sort and print elements once you have _all_ the elements that came before them. Once you add that layer you've got quite a lot more code (and potential for mistakes) than the promises version.
You could also have a mutex-guarded block at the end of every worker goroutine to do the printing and a sync.WaitGroup to follow the workers in main.