&'static str って何だよ

// This is line comments.
// What does &'static str mean? :(
fn fizzbuzz(n: i32) -> &'static str {
    if n % 15 == 0 { "fizzbuzz" }
    else if n % 3 == 0 { "fizz" }
    else if n % 5 == 0 { "buzz" }
    else { "I don't know how to convert type :(" }
}

/// # doc comments
///
/// It supports **Markdown** notation inside. Wow :o
fn main() {
    let n = 1103;
    
    println!("{}", fizzbuzz(n));
}