Raw XML node types—represent arbitrary XML without a schema.

## Overview

This crate provides generic XML types (`Element`, `Content`) that can represent
any XML document without needing predefined Rust structs. It's useful when you
need to parse XML dynamically or work with XML of unknown structure.

## Types

### Element

Captures any XML element with its tag name, attributes, and children:

```rust
use facet_xml_node::Element;

let xml = r#"<item id="42" status="active">Hello <b>world</b></item>"#;
let element: Element = facet_xml::from_str(xml)?;

assert_eq!(element.tag, "item");
assert_eq!(element.attrs.get("id"), Some(&"42".to_string()));
```

### Content

Represents either text or a child element:

```rust
use facet_xml_node::{Element, Content};

for child in &element.children {
    match child {
        Content::Text(t) => println!("Text: {}", t),
        Content::Element(e) => println!("Element: <{}>", e.tag),
    }
}
```

## Use Cases

- Parsing XML of unknown or variable structure
- Building XML transformers or validators
- Bridging between typed and untyped XML representations
- Testing and debugging XML serialization

## Comparison

| Approach | Use Case |
|----------|----------|
| Typed structs with `#[derive(Facet)]` | Known XML schema, compile-time safety |
| `facet-xml-node::Element` | Unknown/dynamic XML, runtime flexibility |
