The String Type
TODO: Figure out if you want to do string literals before this or not. I'm thinking not so that we only have to think about a single string type for the early part of the book. Push the literals to later.
Example showing how to add more text to a mutable String
SOURCE CODE
fn main() {
let mut alfa = String::from("Hello");
println!("alfa is {}", alfa);
alfa.push_str(", World");
println!("alfa is {}", alfa);
}