Use [] instead of () for vec!
Use [] instead of () for vec!

This is the idiomatic and recommended style for this macro.

> (Notice that unlike the println! macro we’ve used in the past, we use
> square brackets [] with vec! macro. Rust allows you to use either in
> either situation, this is just convention.)
>
> https://doc.rust-lang.org/book/vectors.html

sacherjj/rust,exercism/xrust,petertseng/exercism-rust,petertseng/exercism-rust,sacherjj/rust,sacherjj/rust,petertseng/exercism-rust,exercism/xrust