feat(clone_on_ref_ptr): don't add a & to the receiver if it's a reference

[ada4a]

Fixes #15741

changelog: [clone_on_ref_ptr]: don't add a & to the receiver if it's a reference

[rustbot]

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[github-actions]

Lintcheck changes for c831507

Lint	Added	Removed	Changed
clippy::clone_on_ref_ptr	0	0	17

This comment will be updated if you push new changes

[rustbot]

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

[ada4a]

@rustbot ready