Detect incorrect forwarding impls of Display

If forwarding to the inner type's Display is done incorrectly then it won't work properly with many of the nice formatting options that our macros allow us to use.

playpen

use std::fmt;

struct Correct(&'static str);

impl fmt::Display for Correct {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        self.0.fmt(f)
    }
}

struct Incorrect(&'static str);

impl fmt::Display for Incorrect {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "{}", self.0)
    }
}


fn main() {
    println!("{: <10} World", Correct("Hello"));
    println!("{: <10} World", Incorrect("Hello"));
}

Output:

Hello      World
Hello World

Start with the Rust playpen example in the issue, comparing the Correct and Incorrect Display implementations and their formatting output. Identify the lint entry point and existing lint tests for analogous implementation patterns; done means incorrect forwarding implementations are detected while correct formatter forwarding remains accepted.