Fixes and include simple example

examples/stm32f0/src/bin/device.rs

@@ -0,0 +1,21 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use cortex_m_rt::entry;
+use defmt::*;
+use embassy_stm32::device_signature::{device_id, device_id_hex, flash_size_kb};
+use {defmt_rtt as _, panic_probe as _};
+
+#[entry]
+fn main() -> ! {
+    // Example to show how to read the unique id of the mcu
+    info!("Device ID: {:?}", device_id());
+    info!("Device Hex ID: {:?}", device_id_hex());
+    info!("Flash Size in KB = {:?}", flash_size_kb());
+
+    // Main is done, run this future that never finishes
+    loop {
+        let () = core::future::pending().await;
+    }
+}