chore: ⚰️ del unused code

src/a.rs

@@ -1,66 +0,0 @@
-#![no_std]
-#![no_main]
-
-use panic_halt as _;
-
-use avr_device::interrupt;
-use core::cell::RefCell;
-
-type Console = arduino_hal::hal::usart::Usart0<arduino_hal::DefaultClock>;
-static CONSOLE: interrupt::Mutex<RefCell<Option<Console>>> =
-    interrupt::Mutex::new(RefCell::new(None));
-
-macro_rules! print {
-    ($($t:tt)*) => {
-        interrupt::free(
-            |cs| {
-                if let Some(console) = CONSOLE.borrow(cs).borrow_mut().as_mut() {
-                    let _ = ufmt::uwrite!(console, $($t)*);
-                }
-            },
-        )
-    };
-}
-
-macro_rules! println {
-    ($($t:tt)*) => {
-        interrupt::free(
-            |cs| {
-                if let Some(console) = CONSOLE.borrow(cs).borrow_mut().as_mut() {
-                    let _ = ufmt::uwriteln!(console, $($t)*);
-                }
-            },
-        )
-    };
-}
-
-fn put_console(console: Console) {
-    interrupt::free(|cs| {
-        *CONSOLE.borrow(cs).borrow_mut() = Some(console);
-    })
-}
-
-fn subfunction() {
-    println!("We can also call println!() in a subfunction!");
-}
-
-fn demo_print_without_ln() {
-    for i in 0..10 {
-        print!("{} ", i);
-    }
-    println!("numbers!");
-}
-
-#[arduino_hal::entry]
-fn main() -> ! {
-    let dp = arduino_hal::Peripherals::take().unwrap();
-    let pins = arduino_hal::pins!(dp);
-    let serial = arduino_hal::default_serial!(dp, pins, 57600);
-    put_console(serial);
-
-    println!("Hello from main!");
-    subfunction();
-    demo_print_without_ln();
-
-    loop {}
-}