Apply suggestions from code review

Co-authored-by: Diego Barrios Romero <[email protected]>

Author: MorganR

src/digital.rs

@@ -175,7 +175,7 @@ pub trait InputPin {
     fn try_is_low(&self) -> Result<bool, Self::Error>;
 }
 
-/// Single input pin that can switch from input to output mode, and vice-versa.
+/// Single pin that can switch from input to output mode, and vice-versa.
 pub trait IoPin<TInput, TOutput> 
 where TInput : InputPin + IoPin<TInput, TOutput>,
       TOutput : OutputPin + IoPin<TInput, TOutput> {
@@ -192,4 +192,4 @@ where TInput : InputPin + IoPin<TInput, TOutput>,
     /// If the pin is already in the requested state, this method should
     /// succeed.
     fn try_switch_to_output_pin(self, state: PinState) -> Result<TOutput, Self::Error>;
-}
+}