Merge #138

138: Fix some clippy lints r=matklad a=alanhdu

I went ahead and fixed all the clippy lints (there were a couple I thought would be better unfixed and added `cfg` statements to allow them) and also re-enabled clippy and rustfmt in CI.

They were disabled with `no time to explain, disable clippy checks`, so hopefully this won't go against whatever the reason at the time was 😆.

One question about the CI though: right now, it's an allowed failure that runs against the latest nightly each time. Would it be better to pin it to a specific nightly (or use the `beta` versions) to lower the churn?

Co-authored-by: Alan Du <alanhdu@gmail.com>

crates/ra_lsp_server/src/project_model.rs

@@ -173,7 +173,6 @@ pub fn workspace_loader() -> (Worker<PathBuf, Result<CargoWorkspace>>, ThreadWat
         1,
         |input_receiver, output_sender| {
             input_receiver
-                .into_iter()
                 .map(|path| CargoWorkspace::from_cargo_metadata(path.as_path()))
                 .for_each(|it| output_sender.send(it))
         },