Removed unused parameter

Closes angular#3810

Author: avielfedida

modules/angular2/docs/core/02_directives.md

@@ -67,14 +67,14 @@ Here is a trivial example of a tooltip decorator. The directive will log a toolt
  'text: tooltip' | - DOM element tooltip property should be
  ], | mapped to the directive text property.
  host: { | List which events need to be mapped.
- '(mouseover)': 'show()'  | - Invoke the show() method every time
+ '(mouseover)': 'show()' | - Invoke the show() method every time
  } | the mouseover event is fired.
 }) |
 class Form { | Directive controller class, instantiated
  | when CSS matches.
  text:string; | text property on the Directive Controller.
  |
- show(event) { | Show method which implements the show action.
+ show() {  | Show method which implements the show action.
  console.log(this.text); |
  }
 }