Collecting iterators into arrays

[Centril]

@HadrienG

// Won't compile: Strings are not Copy, so they can't be used in array initializers
fn to_owned_arr_loop<'a>(strs: [&'a str; SIZE]) -> [String; SIZE] {
    let mut a = [String::new(); SIZE];
    for (&inp, out) in strs.iter().zip(a.iter_mut()) {
        *out = inp.to_owned();
    }
    a
}

N.B. Tracking issue for RFC 2203, "Constants in array repeat expressions" · Issue #49147 · rust-lang/rust · GitHub, which is probably closer to being fully implemented, will change this such that [const_expr; SIZE]. will work -- However, String::new() isn't a constant expression just yet.