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/buffered_uarte.rs

@@ -15,7 +15,6 @@ use core::slice;
 use core::sync::atomic::{compiler_fence, AtomicU8, AtomicUsize, Ordering};
 use core::task::Poll;
 
-use embassy_cortex_m::interrupt::Interrupt;
 use embassy_hal_common::atomic_ring_buffer::RingBuffer;
 use embassy_hal_common::{into_ref, PeripheralRef};
 use embassy_sync::waitqueue::AtomicWaker;
@@ -24,13 +23,13 @@ pub use pac::uarte0::{baudrate::BAUDRATE_A as Baudrate, config::PARITY_A as Pari
 
 use crate::gpio::sealed::Pin;
 use crate::gpio::{self, AnyPin, Pin as GpioPin, PselBits};
-use crate::interrupt::{self};
+use crate::interrupt::typelevel::Interrupt;
 use crate::ppi::{
     self, AnyConfigurableChannel, AnyGroup, Channel, ConfigurableChannel, Event, Group, Ppi, PpiGroup, Task,
 };
 use crate::timer::{Instance as TimerInstance, Timer};
 use crate::uarte::{apply_workaround_for_enable_anomaly, Config, Instance as UarteInstance};
-use crate::{pac, Peripheral};
+use crate::{interrupt, pac, Peripheral};
 
 mod sealed {
     use super::*;
@@ -77,7 +76,7 @@ pub struct InterruptHandler<U: UarteInstance> {
     _phantom: PhantomData<U>,
 }
 
-impl<U: UarteInstance> interrupt::Handler<U::Interrupt> for InterruptHandler<U> {
+impl<U: UarteInstance> interrupt::typelevel::Handler<U::Interrupt> for InterruptHandler<U> {
     unsafe fn on_interrupt() {
         //trace!("irq: start");
         let r = U::regs();
@@ -202,7 +201,7 @@ impl<'d, U: UarteInstance, T: TimerInstance> BufferedUarte<'d, U, T> {
         ppi_ch1: impl Peripheral<P = impl ConfigurableChannel> + 'd,
         ppi_ch2: impl Peripheral<P = impl ConfigurableChannel> + 'd,
         ppi_group: impl Peripheral<P = impl Group> + 'd,
-        _irq: impl interrupt::Binding<U::Interrupt, InterruptHandler<U>> + 'd,
+        _irq: impl interrupt::typelevel::Binding<U::Interrupt, InterruptHandler<U>> + 'd,
         rxd: impl Peripheral<P = impl GpioPin> + 'd,
         txd: impl Peripheral<P = impl GpioPin> + 'd,
         config: Config,
@@ -237,7 +236,7 @@ impl<'d, U: UarteInstance, T: TimerInstance> BufferedUarte<'d, U, T> {
         ppi_ch1: impl Peripheral<P = impl ConfigurableChannel> + 'd,
         ppi_ch2: impl Peripheral<P = impl ConfigurableChannel> + 'd,
         ppi_group: impl Peripheral<P = impl Group> + 'd,
-        _irq: impl interrupt::Binding<U::Interrupt, InterruptHandler<U>> + 'd,
+        _irq: impl interrupt::typelevel::Binding<U::Interrupt, InterruptHandler<U>> + 'd,
         rxd: impl Peripheral<P = impl GpioPin> + 'd,
         txd: impl Peripheral<P = impl GpioPin> + 'd,
         cts: impl Peripheral<P = impl GpioPin> + 'd,