using full path in the suggestion of clone_on_ref_ptr

[relaxcn]

Fix: #15258

changelog: suggest full path in [clone_on_ref_ptr] to avoid "failed to resolve" error.

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[github-actions]

Lintcheck changes for cfc9b8f

Lint	Added	Removed	Changed
clippy::clone_on_ref_ptr	0	0	91

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[y21]

I wish we had a way to do this in a machine-applicable way, only expanding it if it isn't in scope, but oh well. This works. Thanks!