Fix Never to compile on 1.14 and 1.16

Apparently 1.15 was the only window where this code would be accepted:
rust-lang/rust#40250.

src/encoding/never.rs

@@ -13,22 +13,22 @@ impl Encoding for Never {
     type UnionMembers = Never;
 
     fn descriptor(&self) -> Descriptor<Never, Never, Never, Never> {
-        match self { }
+        match *self { }
     }
 }
 
 impl Encodings for Never {
     fn each<F: EncodingsIterateCallback>(&self, _: &mut F) {
-        match self { }
+        match *self { }
     }
 
     fn eq_encodings<E: ?Sized + Encodings>(&self, _: &E) -> bool {
-        match self { }
+        match *self { }
     }
 }
 
 impl fmt::Display for Never  {
     fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result {
-        match self { }
+        match *self { }
     }
 }