Define the types in the tuple

• Optionally we can define the types of elements of a tuple.
• This can be useful if we don't want the default types. (e.g the default integer type is i32, but here we use i8.)

fn main() {
    let things: (i8, char, String) = (11, '2', String::from("three"));
    println!("{:?}", things);
}

(11, '2', "three")