Function reverse

reverse($root: HTMLElement): string
Generates sillycode markup from the children of a DOM element.

This function extracts text content from DOM elements and converts it back to sillycode markup format. It handles text nodes and element nodes, joining multiple lines with newline characters.
Parameters
- $root: HTMLElement
  The root HTML element to extract content from
Returns string
The generated sillycode markup as a string
Example
```
const element = document.getElementById('editor');
const sillycode = reverse(element);
console.log(sillycode); // "[b]Hello[/b] world"
```
- Defined in dom.ts:27