A Heading

```js
;<div>
  <Heading level={1}>Level 1</Heading>
  <Heading level={2}>Level 2</Heading>
  <Heading level={3}>Level 3</Heading>
  <Heading level={4}>Level 4</Heading>
  <Heading level={5}>Level 5</Heading>
  <Heading level={6}>Level 6</Heading>
</div>
```

Headings are rendered as h1, h2, etc.

H1, H2, etc. components are also exported