refactor: save(to: URL) in case of a manual save dialog

Todos/View/ContentView.swift

@@ -76,16 +76,19 @@ struct ContentView: View {
     }
     
     let ymd = weekStart.formatted(.iso8601.year().month().day())
+    save(to: URL.documentsDirectory.appending(path: "Todo \(ymd).yaml"))
+    weekStart = now
+  }
+  
+  private func save(to: URL) {
     let data = Data(items.map({ $0.yaml() }).joined().utf8)
-    let url = URL.documentsDirectory.appending(path: "Todo \(ymd).yaml")
     do {
-      try data.write(to: url, options: [.atomic, .completeFileProtection])
-      let input = try String(contentsOf: url, encoding: .utf8)
+      try data.write(to: to, options: [.atomic, .completeFileProtection])
+      let input = try String(contentsOf: to, encoding: .utf8)
       print(input)
     } catch {
       print(error.localizedDescription)
     }
-    weekStart = now
   }
   
   private func deleteItem(item: Category) {