PartialEq for TryFromIntError

[leonardo-m]

Regarding code like this:

#![feature(try_from, never_type)]
use std::convert::TryFrom;
use std::num::TryFromIntError;

fn main() {
    let x: u8 = 125;
    let y: Result<u32, !> = u32::try_from(x);
    let _ = y == Ok(125); // OK

    let x: u32 = 125;
    let y: Result<u8, TryFromIntError> = u8::try_from(x);
    let _ = y.ok() == Some(125); // OK

    let x: u32 = 125;
    let y: Result<u8, TryFromIntError> = u8::try_from(x);
    let _ = y == Ok(125); // Error
}

I think I'd like the std library to add #[derive(PartialEq)] to std::num::TryFromIntError, so the last line compiles.

[GuillaumeGomez]

Seems reasonable. Adding it.