Make interrupt module more standard.

- Move typelevel interrupts to a special-purpose mod: `embassy_xx::interrupt::typelevel`.
- Reexport the PAC interrupt enum in `embassy_xx::interrupt`.

This has a few advantages:
- The `embassy_xx::interrupt` module is now more "standard".
  - It works with `cortex-m` functions for manipulating interrupts, for example.
  - It works with RTIC.
- the interrupt enum allows holding value that can be "any interrupt at runtime", this can't be done with typelevel irqs.
- When "const-generics on enums" is stable, we can remove the typelevel interrupts without disruptive changes to `embassy_xx::interrupt`.

embassy-nrf/src/lib.rs

@@ -93,21 +93,16 @@ pub mod wdt;
 #[cfg_attr(feature = "_nrf9160", path = "chips/nrf9160.rs")]
 mod chip;
 
-pub mod interrupt {
-    //! Interrupt definitions and macros to bind them.
-    pub use cortex_m::interrupt::{CriticalSection, Mutex};
-    pub use embassy_cortex_m::interrupt::{Binding, Handler, Interrupt, Priority};
+pub use crate::chip::interrupt;
 
-    pub use crate::chip::irqs::*;
-
-    /// Macro to bind interrupts to handlers.
-    ///
-    /// This defines the right interrupt handlers, and creates a unit struct (like `struct Irqs;`)
-    /// and implements the right [`Binding`]s for it. You can pass this struct to drivers to
-    /// prove at compile-time that the right interrupts have been bound.
-    // developer note: this macro can't be in `embassy-cortex-m` due to the use of `$crate`.
-    #[macro_export]
-    macro_rules! bind_interrupts {
+/// Macro to bind interrupts to handlers.
+///
+/// This defines the right interrupt handlers, and creates a unit struct (like `struct Irqs;`)
+/// and implements the right [`Binding`]s for it. You can pass this struct to drivers to
+/// prove at compile-time that the right interrupts have been bound.
+// developer note: this macro can't be in `embassy-cortex-m` due to the use of `$crate`.
+#[macro_export]
+macro_rules! bind_interrupts {
         ($vis:vis struct $name:ident { $($irq:ident => $($handler:ty),*;)* }) => {
             $vis struct $name;
 
@@ -116,17 +111,16 @@ pub mod interrupt {
                 #[no_mangle]
                 unsafe extern "C" fn $irq() {
                     $(
-                        <$handler as $crate::interrupt::Handler<$crate::interrupt::$irq>>::on_interrupt();
+                        <$handler as $crate::interrupt::typelevel::Handler<$crate::interrupt::typelevel::$irq>>::on_interrupt();
                     )*
                 }
 
                 $(
-                    unsafe impl $crate::interrupt::Binding<$crate::interrupt::$irq, $handler> for $name {}
+                    unsafe impl $crate::interrupt::typelevel::Binding<$crate::interrupt::typelevel::$irq, $handler> for $name {}
                 )*
             )*
         };
     }
-}
 
 // Reexports
 
@@ -136,7 +130,6 @@ pub use chip::pac;
 pub(crate) use chip::pac;
 pub use chip::{peripherals, Peripherals, EASY_DMA_SIZE};
 pub use embassy_cortex_m::executor;
-pub use embassy_cortex_m::interrupt::_export::interrupt;
 pub use embassy_hal_common::{into_ref, Peripheral, PeripheralRef};
 
 pub mod config {