docs(aio): architecture review for a11y (#17848)

PR Close #17848

aio/content/examples/architecture/src/app/hero-detail.component.html

@@ -1,9 +1,10 @@
 <hr>
 <h4>{{hero.name}} Detail</h4>
 <div>Id: {{hero.id}}</div>
-<div>Name:
+<label>Name:
   <!-- #docregion ngModel -->
   <input [(ngModel)]="hero.name">
   <!-- #enddocregion ngModel -->
-</div>
-<div>Power:<input [(ngModel)]="hero.power"></div>
+</label>
+<br />
+<label>Power: <input [(ngModel)]="hero.power"></label>

aio/content/examples/architecture/src/app/sales-tax.component.ts

@@ -7,7 +7,7 @@ import { TaxRateService }  from './tax-rate.service';
   selector:    'app-sales-tax',
   template: `
     <h2>Sales Tax Calculator</h2>
-    Amount: <input #amountBox (change)="0">
+    <label>Amount: <input #amountBox (change)="0"></label>
 
     <div *ngIf="amountBox.value">
     The sales tax is