Integration with NextJS?

Hey there!

Wondering if anyone's integrated this with an mdx setup in Nextjs? 

I've added admonitions to the remarkPlugin array, but no bueno there. Any ideas? 

Thanks! 

```
const withMDX = nextMdx({
  extension: /\.mdx?$/,
  options: {
    remarkPlugins: [remarkGfm, admonitions],
    rehypePlugins: [rehypeSlug],
    providerImportSource: '@mdx-js/react',
  },
})```