fix struct decoder report error

reflect_struct_decoder.go

@@ -995,7 +995,7 @@ func (decoder *structFieldDecoder) Decode(ptr unsafe.Pointer, iter *Iterator) {
 	fieldPtr := decoder.field.UnsafeGet(ptr)
 	decoder.fieldDecoder.Decode(fieldPtr, iter)
 	if iter.Error != nil && iter.Error != io.EOF {
-		iter.Error = fmt.Errorf("%s: %s", decoder.field.Name, iter.Error.Error())
+		iter.Error = fmt.Errorf("%s: %s", decoder.field.Name(), iter.Error.Error())
 	}
 }