docs: 📝 clarify async components for Vue Router

[TheDutchCoder]

Description of Problem

The docs around async components can be a bit confusing when people use Vue Router, hopefully this change clarifies the use of async component with Vue Router a bit.

Proposed Solution

• Change the example of NextPage.vue to a more generic Modal.vue
• Add a note about async components and Vue Router, with a link to the relevant section in the Router docs.

Additional Information

Relates to issue: #1013

[skirtles-code]

Thanks for the PR!

We don't usually reference Vue Router in the main Vue docs but I agree that this is potentially confusing and warrants a mention.

Coming from Vue 2, I thought that async components and lazy loaded routes were effectively the same thing. I imagine a lot of people thought the same. My first reaction when I read this page was that it would be a hassle to upgrade my router config. Hopefully the extra note can help others falling into the same trap.

I've made a couple of suggestions below.

[TheDutchCoder]

@skirtles-code I've updated the examples and also renamed CartFlyout.vue to a more illustrative Modal.vue, which I think is more familiar to people and makes more contextual sense.

Let me know what you think!

[skirtles-code]

Agreed. I prefer Modal too.