Fix examples broken by the macro fix.

examples/stm32h7/src/bin/eth.rs

@@ -106,7 +106,7 @@ async fn main(spawner: Spawner) -> ! {
             let r = socket.write_all(b"Hello\n").await;
             if let Err(e) = r {
                 info!("write error: {:?}", e);
-                return;
+                continue;
             }
             Timer::after(Duration::from_secs(1)).await;
         }

examples/stm32h7/src/bin/eth_client.rs

@@ -108,7 +108,7 @@ async fn main(spawner: Spawner) -> ! {
             let r = connection.write_all(b"Hello\n").await;
             if let Err(e) = r {
                 info!("write error: {:?}", e);
-                return;
+                continue;
             }
             Timer::after(Duration::from_secs(1)).await;
         }

examples/stm32h7/src/bin/i2c.rs

@@ -14,7 +14,7 @@ const ADDRESS: u8 = 0x5F;
 const WHOAMI: u8 = 0x0F;
 
 #[embassy_executor::main]
-async fn main(_spawner: Spawner) -> ! {
+async fn main(_spawner: Spawner) {
     info!("Hello world!");
     let p = embassy_stm32::init(Default::default());