Component: include the linenum JS as part of stacks for Link Previews

[TedGoas]

Following up on #449, @gdalgas wants to:

Would it be possible to include the linenum JS as part of stacks instead of relying on a modified 3rd party library? That way we could have full control over things like naming and implementation. We are using prettify for this currently: https://wet-boew.github.io/v4.0-ci/demos/prettify/prettify-en.html

Yes, let's do that! Aaron suggested changing linenums to s-link-preview--linenumbers while we're there.