docs(demos): update menu demo to use menuClose attribute

demos/menu/index.ts

@@ -25,9 +25,6 @@ class E2EApp {
   }
 
   openPage(menu, page) {
-    // close the menu when clicking a link from the menu
-    menu.close();
-
     // Reset the content nav to have just this page
     // we wouldn't want the back button to show in this scenario
     let nav = this.app.getComponent('nav');

demos/menu/main.html

@@ -8,7 +8,7 @@
 
     <ion-list>
 
-      <button ion-item *ngFor="#p of pages" (click)="openPage(menu, p)">
+      <button ion-item menuClose *ngFor="#p of pages" (click)="openPage(menu, p)">
         {{p.title}}
       </button>