fix pipe overflow when using rustfmt
@@ -576,7 +576,7 @@ pub fn rustfmt_cnt(source: Vec<u8>) -> io::Result<Vec<u8>> {
cmd.stdin(Stdio::piped())
.stdout(Stdio::piped())
- .stderr(Stdio::piped());
+ .stderr(Stdio::null());
let mut child = cmd.spawn()?;
let mut child_stdin = child.stdin.take().unwrap();
