Merge branch 'main' into v4-optional

examples/stm32f7/build.rs

@@ -1,9 +1,8 @@
 //! adapted from https://github.com/stm32-rs/stm32f7xx-hal/blob/master/build.rs
-use std::env;
 use std::fs::File;
 use std::io::prelude::*;
-use std::io::{self};
 use std::path::PathBuf;
+use std::{env, io};
 
 #[derive(Debug)]
 enum Error {