docs: Fix minor typos and coding styles (#35325)

- Fix minor typos in the Getting Started, Forms and AOT Compiler guide.
- Fix minor typo in the Tour of Heroes app.
- Fix coding styles in the Getting Started guide and the Tour of Heroes app

PR Close #35325

aio/content/examples/getting-started/src/app/cart/cart.component.ts

@@ -39,10 +39,10 @@ export class CartComponent implements OnInit {
   // #enddocregion props-services
   onSubmit(customerData) {
     // Process checkout data here
-    console.warn('Your order has been submitted', customerData);
-
     this.items = this.cartService.clearCart();
     this.checkoutForm.reset();
+
+    console.warn('Your order has been submitted', customerData);
   }
 // #docregion props-services, inject-form-builder, checkout-form, checkout-form-group
 }

aio/content/examples/getting-started/src/app/product-details/product-details.component.ts

@@ -39,8 +39,8 @@ export class ProductDetailsComponent implements OnInit {
 // #enddocregion props-methods, get-product
 // #docregion add-to-cart
   addToCart(product) {
-    window.alert('Your product has been added to the cart!');
     this.cartService.addToCart(product);
+    window.alert('Your product has been added to the cart!');
   }
 // #docregion props-methods, get-product, inject-cart-service
 }