Fix Visitor trait fn order & "Nil" str deserialization

Author: Waridley

gdnative-core/src/core_types/variant.rs

@@ -2186,6 +2186,10 @@ pub mod serde {
         where
             E: Error,
         {
+            if v == "Nil" {
+                //`VariantDispatch::Nil` could be represented as the string "Nil"
+                return Ok(Variant::new())
+            }
             Ok(v.to_variant())
         }
 
@@ -2219,7 +2223,14 @@ pub mod serde {
         {
             Ok(().to_variant())
         }
-
+    
+        fn visit_newtype_struct<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
+        where
+            D: Deserializer<'de>,
+        {
+            deserializer.deserialize_any(VariantVisitor)
+        }
+    
         fn visit_seq<A>(self, seq: A) -> Result<Self::Value, <A as SeqAccess<'de>>::Error>
         where
             A: SeqAccess<'de>,
@@ -2229,7 +2240,7 @@ pub mod serde {
                 .visit_seq(seq)
                 .map(VariantArray::<Unique>::owned_to_variant)
         }
-
+    
         fn visit_map<A>(self, map: A) -> Result<Self::Value, <A as MapAccess<'de>>::Error>
         where
             A: MapAccess<'de>,
@@ -2394,13 +2405,6 @@ pub mod serde {
 
             Ok(dict.owned_to_variant())
         }
-
-        fn visit_newtype_struct<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
-        where
-            D: Deserializer<'de>,
-        {
-            deserializer.deserialize_any(VariantVisitor)
-        }
     }
 
     impl<'de> Deserialize<'de> for Variant {