Rollup merge of #149781 - mu001999-contrib:fix/149756, r=jdonszelmann

Don't suggest wrapping attr in unsafe if it may come from proc macro

Don't emit the suggestion if the span may come from proc macro. Check this with the snippet because we cannot check if the span is from macro-rules or proc-macro (maybe this can happen in the future?).

Fixes rust-lang/rust#149756

Author: matthiaskrgr