Use `.share()` instead of `.clone()`

What it does

This lint should suggest using std::clone::Share::share over std::clone::Clone::clone where applicable.

Advantage

The purpose of the Share trait is to make the behavior of Clone more explicit. share is the exact same as clone, but expresses intent and semantics more clearly, so it would be useful to have a lint to suggest turning the former into the latter.

Drawbacks

The obvious drawback is that Share is currently experimental, so implementing a lint for it at this stage might be wasted effort, although from what I can tell it does seem rather finalized. This suggestion is mostly intended for when/if Share does stabilize.

Another drawback is that calling share requires importing std::clone::Share, which might be seen as unnecessary import bloat.

Example

let a = Rc::new(621);
let b = a.clone();

Could be written as:

let a = Rc::new(621);
let b = a.share();

Comparison with existing lints

As far as I know, there is currently no lint or suggestion(s) for one which cover this.

Additional Context

No response

No files, tests, or entry points are named. Start by locating Clippy's existing clone-related lints and their tests, then determine the stabilization and applicability requirements for std::clone::Share. Done means a lint can reliably suggest .share() instead of .clone() where applicable, with coverage for the example and relevant edge cases.