Issue #590 (#591)

* Removed MobX Todos unused observable #529

* updated example code with latest json_serializable

* synced todo list example docs with latest code

docs/docs/examples/todos/index.mdx

@@ -46,7 +46,7 @@ Next comes the `TodoList`, which manages a list of `Todo`s. The core-state of `T
 
 - [x] a list of `Todo`s
 - [x] a `filter` that tracks the visibility-filter applied on the list of todos
-- [x] the `currentDescription`, which tracks the description entered by the user for a new todo.
+
 
 This can be seen with the `@observable` properties.
 
@@ -66,9 +66,6 @@ abstract class _TodoList with Store {
  @observable
  VisibilityFilter filter = VisibilityFilter.all;
 
- @observable
- String currentDescription = '';
-
 }
 ```
 
@@ -149,17 +146,14 @@ abstract class _TodoList with Store {
  void addTodo(String description) {
  final todo = Todo(description);
  todos.add(todo);
- currentDescription = '';
  }
 
  @action
  void removeTodo(Todo todo) {
  todos.removeWhere((x) => x == todo);
  }
 
- @action
- void changeDescription(String description) =>
- currentDescription = description;
+
 
  @action
  void changeFilter(VisibilityFilter filter) => this.filter = filter;
@@ -194,9 +188,6 @@ abstract class _TodoList with Store {
  @observable
  VisibilityFilter filter = VisibilityFilter.all;
 
- @observable
- String currentDescription = '';
-
  @computed
  ObservableList<Todo> get pendingTodos =>
  ObservableList.of(todos.where((todo) => todo.done != true));
@@ -245,18 +236,13 @@ abstract class _TodoList with Store {
  void addTodo(String description) {
  final todo = Todo(description);
  todos.add(todo);
- currentDescription = '';
  }
 
  @action
  void removeTodo(Todo todo) {
  todos.removeWhere((x) => x == todo);
  }
 
- @action
- void changeDescription(String description) =>
- currentDescription = description;
-
  @action
  void changeFilter(VisibilityFilter filter) => this.filter = filter;
 
@@ -380,7 +366,7 @@ class TodoListView extends StatelessWidget {
 
 **AddTodo**
 
-Similarly, here is the `AddTodo` widget that observes the `list.currentDescription` and also fires the `list.changeDescription` action.
+Similarly, here is the `AddTodo` widget that fires the `list.addTodo` action.
 
 ```dart
 class AddTodo extends StatelessWidget {
@@ -395,9 +381,7 @@ class AddTodo extends StatelessWidget {
  decoration: const InputDecoration(
  labelText: 'Add a Todo', contentPadding: EdgeInsets.all(8)),
  controller: _textController,
- onChanged: (String newValue) {
- list.currentDescription = newValue;
- },
+ textInputAction: TextInputAction.done,
  onSubmitted: (String value) {
  list.addTodo(value);
  _textController.clear();