Invalid HTML should be handled as good as possible

**Minimal HTML example**

```
<p>subject321</p><html><head></head><body>body123</body></html>
``` 

**Options**

default options

**Observed output**

```
body123
```

**Expected output**

```
subject321body123
```

**Version information**

- html-to-text: 9.0.5
- node: 

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