Clean up trailing space and fix rhai_runner print out

examples/simple_fn.rs

@@ -9,7 +9,7 @@ fn main() {
     let mut engine = Engine::new();
 
     engine.register_fn("add", add);
- 
+
     if let Ok(result) = engine.eval::<i32>("add(40, 2)") {
        println!("Answer: {}", result);  // prints 42
     }