remove uselessly wrapped ?s. (clippy::meedless_question_mark

let x = Some(3);

let y = Some(x?);
can just be:
let y = x

crates/proc_macro_api/src/process.rs

@@ -154,5 +154,5 @@ fn send_request(
     req: Request,
 ) -> io::Result<Option<Response>> {
     req.write(&mut writer)?;
-    Ok(Response::read(&mut reader)?)
+    Response::read(&mut reader)
 }