docs(annotations): fix typo, align docs with code

Closes angular#1045

Author: SekibOmazic

modules/angular2/src/core/annotations/annotations.js

@@ -660,7 +660,7 @@ export class DynamicComponent extends Directive {
  *   bind: {
  *     'text': 'tooltip'
  *   },
- *   event: {
+ *   events: {
  *     'onmouseenter': 'onMouseEnter()',
  *     'onmouseleave': 'onMouseLeave()'
  *   }