Fix type wrapping order

Types were being wrapped inside out, i.e. if you have some nested type A.B.C.D, the partial type
for D was being synthesized as C.B.A.D. This fixes the order for both serialization and deserialization.

src/generator/TypeDeclContext.cs

@@ -39,6 +39,8 @@ public TypeDeclContext(BaseTypeDeclarationSyntax typeDecl)
                         break;
                 }
             }
+            nsNames.Reverse();
+            parentTypeInfos.Reverse();
             NamespaceNames = nsNames;
             ParentTypeInfo = parentTypeInfos;
             TypeParameterList = typeDecl is TypeDeclarationSyntax derived

test/Serde.Generation.Test/DeserializeTests.cs

@@ -177,6 +177,30 @@ public enum ColorULong : ulong { Red = 3, Green = 5, Blue = 7 }
             return GeneratorTestUtils.VerifyMultiFile(src);
         }
 
+        [Fact]
+        public Task NestedPartialClasses()
+        {
+            var src = """
+using Serde;
+
+partial class A
+{
+    private partial class B
+    {
+        private partial class C
+        {
+            [GenerateDeserialize]
+            private partial class D
+            {
+                public int Field;
+            }
+        }
+    }
+}
+""";
+            return VerifyDeserialize(src);
+        }
+
         private static Task VerifyDeserialize(
             string src,
             [CallerMemberName] string caller = "")

test/Serde.Generation.Test/SerializeTests.cs

@@ -560,6 +560,30 @@ public enum Rgb { Red, Green, Blue }
             return VerifyMultiFile(src);
         }
 
+        [Fact]
+        public Task NestedPartialClasses()
+        {
+            var src = """
+using Serde;
+
+partial class A
+{
+    private partial class B
+    {
+        private partial class C
+        {
+            [GenerateSerialize]
+            private partial class D
+            {
+                public int Field;
+            }
+        }
+    }
+}
+""";
+            return VerifySerialize(src);
+        }
+
         private static Task VerifySerialize(
             string src,
             [CallerMemberName] string callerName = "")