Go 1.19 started reformatting code in a way that makes it more obvious
how it will be rendered on pkg.go.dev. It gets it almost right, but not
entirely. Therefore, I had to modify some of the comments so that they
are formatted correctly.
This is necessary to avoid a circular dependency between the device/avr
and runtime/interrupts package in the next commit.
It may be worth replacing existing calls like device/arm.Asm to
device.Asm, to have a single place where these are defined.