[DOC] add dedicated page on event handling

part of #632

doc/learning/overview.md

@@ -124,7 +124,7 @@ class Parent extends Component {
 In this example, the `OrderLine` component trigger a `add-to-order` event. This
 will generate a DOM event which will bubble along the DOM tree. It will then be
 intercepted by the parent component, which will then get the line (from the
-`detail` key) and then increment its quantity. See the section on [event handling](../reference/component.md#event-handling)
+`detail` key) and then increment its quantity. See the page on [event handling](../reference/event_handling.md)
 for more details on how events work.
 
 Note that this example would have also worked if the `OrderLine` component

doc/learning/tutorial_todoapp.md

@@ -446,7 +446,7 @@ Now, this is an interesting situation: the task is displayed by the `Task`
 component, but it is not the owner of its state, so it cannot modify it. Instead,
 we want to communicate the request to toggle a task to the `App` component.
 Since `App` is a parent of `Task`, we can
-[trigger](../reference/component.md#event-handling) an event in `Task` and listen
+[trigger](../reference/event_handling.md) an event in `Task` and listen
 for it in `App`.
 
 In `Task`, change the `input` to: