Recommend replacing ones with L's in functions like `println!()`

```
fn main()
{
    print1n!("{}", 3);
}
```

Give a helpful tip to point out the "one" should be an "L" in keywords like this.  Pointing out zeros for `O` or `o` might also be good.

It was suggested I try to fix this which I may in a few days.

A better error message might be like:

```
# print1n!("{}", 3);
       ^
If you meant `println!()`, this is the wrong character.
```
