Fix name of trait for embedded-hal 1.0 and add missing import (google…

…#2174)

src/exercises/bare-metal/compass.md

@@ -12,8 +12,8 @@ Hints:
   as the [micro:bit hardware](https://tech.microbit.org/hardware/).
 - The LSM303AGR Inertial Measurement Unit is connected to the internal I2C bus.
 - TWI is another name for I2C, so the I2C master peripheral is called TWIM.
-- The LSM303AGR driver needs something implementing the
-  `embedded_hal::blocking::i2c::WriteRead` trait. The
+- The LSM303AGR driver needs something implementing the `embedded_hal::i2c::I2c`
+  trait. The
   [`microbit::hal::Twim`](https://docs.rs/microbit-v2/latest/microbit/hal/struct.Twim.html)
   struct implements this.
 - You have a
@@ -33,7 +33,7 @@ _src/main.rs_:
 
 ```rust,compile_fail
 {{#include compass/src/main.rs:top}}
-use microbit::{hal::uarte::{Baudrate, Parity, Uarte}, Board};
+use microbit::{hal::{Delay, uarte::{Baudrate, Parity, Uarte}}, Board};
 
 {{#include compass/src/main.rs:main}}
     // TODO