Split function into files

---

examples/other/project/src/main.rs

pub mod helper;

fn main() {
    println!("main");
    same_file();
    helper::public_in_helper();
    //helper::private_in_helper();
}

fn same_file() {
    println!("same file");
}

examples/other/project/src/helper.rs

pub fn public_in_helper() {
    println!("public_in_helper");
    private_in_helper();
}

fn private_in_helper() {
    println!("in_helper");
}

examples/other/project/Cargo.toml

[package]
name = "project"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]