Fix up the SPI example pins comment too

Author: 9names

rp2040-hal-examples/src/bin/spi.rs

@@ -78,7 +78,7 @@ fn main() -> ! {
         &mut pac.RESETS,
     );
 
-    // These are implicitly used by the spi driver if they are in the correct mode
+    // Set up our SPI pins so they can be used by the SPI driver
     let spi_mosi = pins.gpio7.into_function::<hal::gpio::FunctionSpi>();
     let spi_miso = pins.gpio4.into_function::<hal::gpio::FunctionSpi>();
     let spi_sclk = pins.gpio6.into_function::<hal::gpio::FunctionSpi>();