Fix incorrect JSON handling code on Networking page (#1087)

Author: AzureMarker

templates/components/what/networking/take-json.hbs

@@ -1,8 +1,8 @@
-#[derive(FromForm)]
+#[derive(Deserialize)]
 struct Task { name: String, completed: bool }
 
 #[post("/", data = "<task>")]
-fn new(task: Form<Task>) -> Flash<Redirect> {
+fn new(task: Json<Task>) -> Flash<Redirect> {
     if task.name.is_empty() {
         Flash::error(Redirect::to("/"),
             "Cannot be empty.")