Prereleased 2026-05-19

• Use marker struct instead of address in Periph with PeripheralSpec trait
• Add --skip-peripherals-struct flag to skip generating the Peripherals
  struct, its take/steal impl and the DEVICE_PERIPHERALS static
• Generated cortex-m PACs now implement the cortex_m_types::InterruptNumber trait instead of
  the cortex-m::interrupt::InterruptNumber trait. A new add-cortex-m-int-num option
  which allows adding the generation of the old trait.
• Bump MSRV of generated code to 1.81