chore: Create script to check for outdated keyToCss keys

[marcustyphoon]

Description

Here's a quick and dirty script that checks if we call keyToCss with keys that are no longer in the CSS map. Much easier than adding logging to the function and trying to find them in practice.

I was hoping to do something based on AST parsing, but eh, that sounds like a lot of work. https://xkcd.com/208/ it is.

Totally don't have to commit this.

> dev/check-outdated-css-keys.js
keyToCss is called with outdated/invalid arguments:
- reblogTrailWrapper
- hasPermalink
- withTrailItemPermalink
- isReblogWithAddedContent
- heightRestrictorExpandButtonWrapper
- contentWarningCover
- expandTagsButtonWrapper
- notifications
- videoCTA

Testing steps

Run dev/check-outdated-css-keys.js.

[AprilSylph]

Useful!

Also yes I like Sets, delicious thank you.