docs(cheatsheet): update to new syntax

See https://github.com/angular/angular.io/pull/459

Closes #5733

modules/angular2/docs/cheatsheet/lifecycle hooks.md

@@ -5,45 +5,63 @@ Directive and component change detection and lifecycle hooks
 (implemented as class methods)
 
 @cheatsheetItem
+syntax:
 `constructor(myService: MyService, ...) { ... }`|`constructor(myService: MyService, ...)`
+description:
 The class constructor is called before any other lifecycle hook. Use it to inject dependencies, but avoid any serious work here.
 
 
 @cheatsheetItem
+syntax:
 `ngOnChanges(changeRecord) { ... }`|`ngOnChanges(changeRecord)`
+description:
 Called after every change to input properties and before processing content or child views.
 
 
 @cheatsheetItem
+syntax:
 `ngOnInit() { ... }`|`ngOnInit()`
+description:
 Called after the constructor, initializing input properties, and the first call to ngOnChanges.
 
 
 @cheatsheetItem
+syntax:
 `ngDoCheck() { ... }`|`ngDoCheck()`
+description:
 Called every time that the input properties of a component or a directive are checked. Use it to extend change detection by performing a custom check.
 
 
 @cheatsheetItem
+syntax:
 `ngAfterContentInit() { ... }`|`ngAfterContentInit()`
+description:
 Called after ngOnInit when the component's or directive's content has been initialized.
 
 
 @cheatsheetItem
+syntax:
 `ngAfterContentChecked() { ... }`|`ngAfterContentChecked()`
+description:
 Called after every check of the component's or directive's content.
 
 
 @cheatsheetItem
+syntax:
 `ngAfterViewInit() { ... }`|`ngAfterViewInit()`
+description:
 Called after ngAfterContentInit when the component's view has been initialized. Applies to components only.
 
 
 @cheatsheetItem
+syntax:
 `ngAfterViewChecked() { ... }`|`ngAfterViewChecked()`
+description:
 Called after every check of the component's view. Applies to components only.
 
 
 @cheatsheetItem
+syntax:
 `ngOnDestroy() { ... }`|`ngOnDestroy()`
+description:
 Called once, before the instance is destroyed.