dwt: mark ComparatorFunction, DwtError as non-exhaustive

A DWT unit can do much more than just comparing addresses. PC
comparison, for example, which is only possible with the first DWT unit.

Author: tmplt

src/peripheral/dwt.rs

@@ -346,13 +346,15 @@ pub struct ComparatorAddressSettings {
 
 /// The available functions of a DWT comparator.
 #[derive(Debug)]
+#[non_exhaustive]
 pub enum ComparatorFunction {
     /// Compare accessed memory addresses.
     Address(ComparatorAddressSettings),
 }
 
 /// Possible error values returned on [Comparator::configure].
 #[derive(Debug)]
+#[non_exhaustive]
 pub enum DwtError {
     /// Invalid combination of [AccessType] and [EmitOption].
     InvalidFunction,