cedar-go/types: embed Stringer in Value interface instead of redefini…

…ng it

Signed-off-by: Patrick Jakubowski <[email protected]>

types/value.go

@@ -12,8 +12,7 @@ var ErrIP = fmt.Errorf("error parsing ip value")
 // Implementations of Value _must_ be able to be safely copied shallowly, which means they must either be immutable
 // or be made up of data structures that are free of pointers (e.g. slices and maps).
 type Value interface {
-	// String produces a string representation of the Value.
-	String() string
+	fmt.Stringer
 	// MarshalCedar produces a valid MarshalCedar language representation of the Value.
 	MarshalCedar() []byte
 	// ExplicitMarshalJSON marshals the Value into JSON using the explicit (if