VirtualKeyboard API Doc Tweaks

### MDN URL

https://developer.mozilla.org/en-US/docs/Web/API/VirtualKeyboard_API

### What specific section or headline is this issue about?

_No response_

### What information was incorrect, unhelpful, or incomplete?

The page could benefit from these improvements:

- I think that page should make a distinction between the visual viewport and the layout viewport. It's - by default - only the visual viewport that gets resized when the Virtual Keyboard gets shown. The Layout Viewport remains untouched.
- There's also a link with https://developer.mozilla.org/en-US/docs/Web/HTML/Viewport_meta_tag#the_effect_of_interactive_ui_widgets, which can be used to opt into the overlayscontent behavior.

### What did you expect to see?

See above.

### Do you have any supporting links, references, or citations?

- https://github.com/bramus/viewport-resize-behavior/blob/main/explainer.md
- https://developer.chrome.com/blog/viewport-resize-behavior/
- https://developer.mozilla.org/en-US/docs/Web/HTML/Viewport_meta_tag#the_effect_of_interactive_ui_widgets

### Do you have anything more you want to share?

_No response_

### MDN metadata

Page report details

* Folder: `en-us/web/api/virtualkeyboard_api`
* MDN URL: https://developer.mozilla.org/en-US/docs/Web/API/VirtualKeyboard_API
* GitHub URL: https://github.com/mdn/content/blob/main/files/en-us/web/api/virtualkeyboard_api/index.md
* Last commit: https://github.com/mdn/content/commit/2fc10b6e2ac7888cef38fa356432a093b5d6dddd
* Document last modified: 2023-01-11T20:05:07.000Z