Warn if the order of impl trait functions is not the same as in trait definition

What it does

In the following example, the ordering of trait functions is different from implementation. It is usually better for consistency when all implementations follow the same fn order as defined in the trait. Probably pedantic?

Advantage

• the ordering is consistent between all trait implementations, making it easier to read

Drawbacks

• code churn if not done right from the start

Example

trait Animal {
    fn make_sound(&self);
    fn eat(&self);
}

struct Cow;

impl Animal for Cow {
    fn eat(&self) { println!("grass"); }
    fn make_sound(&self) { println!("moo"); }
}

Could be written as (change fn ordering)

impl Animal for Cow {
    fn make_sound(&self) { println!("moo"); }
    fn eat(&self) { println!("grass"); }
}

Start with the trait and implementation examples in the issue and review how Clippy lints inspect trait implementations. Determine the appropriate lint scope and whether it belongs under pedantic; done means a differing function order produces the intended warning without false positives.