Remove stub from `example.rs`
-//! Example implementation for armstrong-numbers
-//!
-//! - Implement the solution to your exercise here.
-//! - Put the stubs for any tested functions in `src/lib.rs`,
-//! whose variable names are `_` and
-//! whose contents are `unimplemented!()`.
-//! - If your example implementation has dependencies, copy
-//! `Cargo.toml` into `Cargo-example.toml` and then make
-//! any modifications necessary to the latter so your example will run.
-//! - Test your example by running `../../bin/test-exercise`
-
pub fn is_armstrong_number(num: u32) -> bool {
let s = format!("{}", num);
let l = s.len();
