Add remarkRehypeOptions and rehypeStringifyOptions to provide options to default Markdown processors

[causztic]

#202

This is the minimum amount of work to allow custom options to be passed to the default processors to allow raw HTML tags among other things

Let me know if automated tests are required (I don't see any for the existing code in markdown.ts..)

Here are some screenshots that were taken during testing (using examples/next-contentlayer-example):

When the options are excluded, there are no errors

With the following options in examples/next-contentlayer-example/contentlayer.config.ts

  markdown: {
    remarkRehypeOptions: { allowDangerousHtml: true },
    rehypeStringifyOptions: { allowDangerousHtml: true }
  }

When including the options, it is passed down correctly and renders raw HTML as expected

[changeset-bot]

🦋 Changeset detected

Latest commit: 0c23653

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 9 packages

Name	Type
@contentlayer/core	Patch
@contentlayer/cli	Patch
@contentlayer/client	Patch
@contentlayer/source-contentful	Patch
@contentlayer/source-files	Patch
@contentlayer/source-sanity	Patch
contentlayer-stackbit-yaml-generator	Patch
contentlayer	Patch
next-contentlayer	Patch

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[causztic]

Not sure whether I did the changeset properly (this is new to me!), please let me know if it's done wrongly

[schickling]

Thanks a lot for this PR @causztic. Closing based on our chat in Discord and given the upcoming 0.2.5 release (see here)

[causztic]

Thank you for the work! 🙇