Remove trait_alias, allow(incomplete_features).

trait_alias seems unused. no idea why it's there.

examples/stm32g0/src/bin/blinky.rs

@@ -1,8 +1,6 @@
 #![no_std]
 #![no_main]
-#![feature(trait_alias)]
 #![feature(type_alias_impl_trait)]
-#![allow(incomplete_features)]
 
 #[path = "../example_common.rs"]
 mod example_common;

examples/stm32g0/src/bin/button.rs

@@ -1,8 +1,6 @@
 #![no_std]
 #![no_main]
-#![feature(trait_alias)]
 #![feature(type_alias_impl_trait)]
-#![allow(incomplete_features)]
 
 #[path = "../example_common.rs"]
 mod example_common;

examples/stm32g0/src/bin/button_exti.rs

@@ -1,8 +1,6 @@
 #![no_std]
 #![no_main]
-#![feature(trait_alias)]
 #![feature(type_alias_impl_trait)]
-#![allow(incomplete_features)]
 
 #[path = "../example_common.rs"]
 mod example_common;