hello-world: clarify "says"

[kevinlitchfield]

I think it could be worthwhile to clarify what "says" means in the exercise description. Often, "Hello, World!" programs print Hello, World! to the screen, but the Exercism exercises I've seen instead ask for a function that returns the string Hello, World!.

Because "says" could sound like it's figuratively referring to printing to the screen, and because a learner familiar with "Hello, World!" programs might expect to write a program that prints Hello, World! to the screen, I think "returns the string" might be clearer here.

Thoughts?

[stkent]

+1 this. I think there are other exercises that could also benefit from the same adjustment (diamond springs to mind; I think that explicitly uses "prints", but most (all?) implementations return a list of strings).

[petertseng]

Thanks. Yeah, we should have paid attention to exercism/exercism#2746 when doing #544.

Just as you edited the PR title to include hello-world, going to amend the commit message to also do so.