Log rustfmt parsing errors as warnings We unconditionally pass an edition parameter to rustfmt, for some crates this might fail rustfmt so instead of swallowing the error, at least Log it on a level that is logged by default so users won't be completely confused about it. See for context https://github.com/rust-lang/rust-analyzer/issues/10209 Closes https://github.com/rust-lang/rust-analyzer/issues/10209