Add styling for Code Blocks

[SavePointSam]

This adds the styling of code block on the old website back onto the new one. Due to a glitch on Docusaurus, the Tomorrow theme needed to be added manually for Highlight.js

[babel-bot]

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Built with commit 3763699

https://deploy-preview-1532--babel.netlify.com

[JoelMarcey]

@SavePointSam Hi. Do you think we could use this (or some variation) as an upstream patch to Docusaurus? I certainly do not mind pushing out a bug fix release of Docusaurus if that helps things along here.

[SavePointSam]

Hey @JoelMarcey, this PR is just to add styling for the new Babel site. I'm not sure what you'd want to pull out of here and put into Docusaurus. What were you thinking to add? It's mostly just CSS. Personally, I wouldn't want to add the CSS I wrote here to Docusaurus. It was just making the most of what I had available to me.

I'd rather post a PR to Docusaurus in order to add the changes I've made here in more maintainable and proper way. Would you be interested in me adding the code block headers? I can write something up and have a PR rather quickly.

[hzoo]

Fine with just landing this for now since it's just 2 standalone css files and we can remove later if we find another solution or it's fixed in docusaurus later.

[hzoo]

Thanks @SavePointSam, awesome

[JoelMarcey]

@SavePointSam Yeah, it is possible I misunderstood the overall intent of this PR yesterday -- I saw "glitch in Docusaurus" and thought there was maybe something that could have been upstreamed to fix to better support "Tomorrow".