Fix doc comment

Author: bugadani

examples/tcpdump.rs

@@ -1,7 +1,7 @@
 use smoltcp::phy::{Device, RxToken};
 use smoltcp::time::Instant;
 use smoltcp::wire::{EthernetFrame, PrettyPrinter};
-use smoltcp_device_unix::{wait as phy_wait, RawSocket};
+use smoltcp_device_unix::{RawSocket, wait as phy_wait};
 use std::env;
 use std::os::unix::io::AsRawFd;
 

smoltcp-device/src/lib.rs

@@ -15,8 +15,7 @@ An implementation of the [Device](trait.Device.html) trait for a simple hardware
 Ethernet controller could look as follows:
 
 ```rust
-use smoltcp_device::{DeviceCapabilities, Device, Medium};
-use smoltcp::time::Instant;
+use smoltcp_device::{DeviceCapabilities, Device, Medium, time::Instant};
 
 struct StmPhy {
     rx_buffer: [u8; 1536],