Use nightly for style check (#396)

* Use nightly for style check

Signed-off-by: Michael X. Grey <mxgrey@intrinsic.ai>

* Install nightly for cargo +nightly fmt

Signed-off-by: Michael X. Grey <mxgrey@intrinsic.ai>

* Fix style in examples

Signed-off-by: Michael X. Grey <mxgrey@intrinsic.ai>

* Update style for rosidl_runtime_rs

Signed-off-by: Michael X. Grey <mxgrey@intrinsic.ai>

* Add a comment indicating that nightly release is needed for formatting

Signed-off-by: Michael X. Grey <mxgrey@intrinsic.ai>

---------

Signed-off-by: Michael X. Grey <mxgrey@intrinsic.ai>

Author: mxgrey

rclrs/message_demo/src/message_demo.rs

@@ -1,6 +1,4 @@
-use std::convert::TryInto;
-use std::env;
-use std::sync::Arc;
+use std::{convert::TryInto, env, sync::Arc};
 
 use anyhow::{Error, Result};
 use rosidl_runtime_rs::{seq, BoundedSequence, Message, Sequence};

rclrs/minimal_pub_sub/src/minimal_two_nodes.rs

@@ -1,6 +1,10 @@
-use std::env;
-use std::sync::atomic::{AtomicU32, Ordering};
-use std::sync::{Arc, Mutex};
+use std::{
+    env,
+    sync::{
+        atomic::{AtomicU32, Ordering},
+        Arc, Mutex,
+    },
+};
 
 use anyhow::{Error, Result};