Downgrade needless_pass_by_value to allow by default

I noticed that I suppress this lint in many of my projects.

https://github.com/search?q=needless_pass_by_value+user%3Adtolnay&type=Code
https://github.com/search?q=needless_pass_by_value+user%3Aserde-rs&type=Code

Upon further inspection, this lint has a *long* history of false
positives (and several remaining).

Generally I feel that this lint is the definition of pedantic and should
not be linted by default.

    #[derive(Debug)]
    enum How {
        ThisWay,
        ThatWay,
    }

    // Are we really better off forcing the call sites to write f(&_)...?
    fn f(how: How) {
        println!("You want to do it {:?}", how);
    }

    fn main() {
        f(How::ThatWay);
    }

0 files changed, 0 insertions, 0 deletions