Validate after parsing

[vallentin]

Simply swapped around parsing and validating. If it successfully parses, then validate. Since if parsing fails, then it doesn't matter if it was validated.

Example:

Input::<i32>::new()
    .validate_with(|_input: &str| -> Result<(), &str> {
        println!("Validate");
        Ok(())
    })
    .interact()
    .unwrap();

Before if you entered foo, then it would display:

Validate
error: invalid digit found in string

[pksunkara]

Cherry picked this.