Add type info change in docs

substrate/primitives/runtime/src/type_with_default.rs

@@ -40,6 +40,7 @@ use serde::{Deserialize, Serialize};
 /// A type that wraps another type and provides a default value.
 ///
 /// Passes through arithmetical and many other operations to the inner value.
+/// Type information for metadata is the same as the inner value's type.
 #[derive(Encode, Decode, Debug, MaxEncodedLen)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct TypeWithDefault<T, D: Get<T>>(T, PhantomData<D>);