<define-element>

Has same signature as `` but for defining a custom-element.

```html

0

```

It only fetch then apply linked modules when the custom-element is in view.

> **Note** that it use `root=open/closed` instead of `shadowroot=open/closed` to avoid ghosted elements

> **Warning** it may cause layout shift

## TODO
- [ ] define custom-element
- [ ] `extends` from existing `HTML<*>Element`
- [ ] delete custom-element from registry when disconnected from document
- [ ] immediate query and lazy bind on every `slotchange`

## Related
### [Declarative Syntax for Custom Elements](https://github.com/WICG/webcomponents/blob/gh-pages/proposals/Declarative-Custom-Elements-Strawman.md) (strawman proposal)
Maybe *partially* rewriting the current implementation as module 🤔
> **Warning**: Don't ever rewrite `` as module!
```html

import { scope } from "nusa"
@scope
class MyElement extends HTMLFormElement {
/* ~ */
}

```