docs(demos): update loading API demo

demos/loading/index.ts

@@ -91,7 +91,19 @@ class E2EPage {
   }
 
   goToPage2() {
-    this.nav.push(Page2);
+    let loading = Loading.create({
+      content: 'This will navigate to the next page and then dismiss after 3 seconds.'
+    });
+
+    this.nav.present(loading);
+
+    setTimeout(() => {
+      this.nav.push(Page2);
+    }, 1000);
+
+    setTimeout(() => {
+      loading.dismiss();
+    }, 4000);
   }
 }
 
@@ -100,7 +112,7 @@ class E2EPage {
     <ion-navbar *navbar>
       <ion-title>Page 2</ion-title>
     </ion-navbar>
-    <ion-content padding>Some content</ion-content>
+    <ion-content padding>This is another page!</ion-content>
   `
 })
 class Page2 {

demos/loading/main.html

@@ -9,27 +9,27 @@
     </ion-list-header>
     <button ion-item (click)="presentLoadingIos()">
       <ion-spinner item-left name="ios"></ion-spinner>
-      Preview iOS
+      Show iOS
     </button>
     <button ion-item (click)="presentLoadingDots()">
       <ion-spinner item-left name="dots"></ion-spinner>
-      Preview Dots
+      Show Dots
     </button>
     <button ion-item (click)="presentLoadingBubbles()">
       <ion-spinner item-left name="bubbles"></ion-spinner>
-      Preview Bubbles
+      Show Bubbles
     </button>
     <button ion-item (click)="presentLoadingCircles()">
       <ion-spinner item-left name="circles"></ion-spinner>
-      Preview Circles
+      Show Circles
     </button>
     <button ion-item (click)="presentLoadingCrescent()">
       <ion-spinner item-left name="crescent"></ion-spinner>
-      Preview Crescent
+      Show Crescent
     </button>
     <button ion-item (click)="presentLoadingDefault()">
       <ion-spinner item-left></ion-spinner>
-      Preview Default
+      Show Default
     </button>
   </ion-list>
 
@@ -38,10 +38,10 @@
       Custom Loading Indicators
     </ion-list-header>
     <button ion-item (click)="presentLoadingCustom()">
-      Preview Custom
+      Show Custom
     </button>
     <button ion-item (click)="presentLoadingText()">
-      Preview Text Only
+      Show Text Only
     </button>
   </ion-list>
 
@@ -50,7 +50,7 @@
 <ion-toolbar position="bottom">
   <ion-buttons end>
     <button (click)="goToPage2()">
-      Navigate
+      Show Loading and Navigate
       <ion-icon name="arrow-forward"></ion-icon>
     </button>
   </ion-buttons>