Example code fixes

[Peter Martin]

Hi, thanks for an excellent driver for the pico. Just one small issue in the API document. I think the example code should read:

// Enable irqs
irq_set_exclusive_handler(PIO0_IRQ_0_IRQn, PIOx_IRQHandler);

The irq_set_exclusive_handler has the arguments swapped.

[KevinOConnor]

Thanks. Should be fixed now (commit 6355c1b).

-Kevin