Fix enum problems in config

src/fetchers/jnovel.rs

@@ -95,6 +95,15 @@ pub(crate) struct JNovelFetcher {
     series_has_parts: bool
 }
 
+impl Default for JNovelFetcher {
+    fn default() -> Self {
+        Self {
+            series_slug: "".to_owned(),
+            series_has_parts: false,
+        }
+    }
+}
+
 impl JNovelFetcher {
     pub(crate) fn set_series(&mut self, series: String) {
         self.series_slug = series;