feat(macros): rewrite CSSSyntax macro (#4656)

* New CSSSyntax macro

* Highlight properties

* Call property class a property class

* Simplify CSS class stuff

* Link to externally described types

* Linkify brackets and combinators

* Use browser-compat to figure out which spec to get the data from

* Random updates

* Resolve syntax only using webref

* Fix links when value includes range

* Require new version of webref/css

* Cleanup, reorg, comments

* Don't use angled brackets for the property name

* Remove cssesc which had snuck back in

* test: check flaws with toEqual()

If we encounter flaws unexpectedly, this surfaces it in the output.

* fix(macros/CSSSyntax): use shim for String.prototype.replaceAll

* Update kumascript/macros/CSSSyntax.ejs

Co-authored-by: Claas Augner <github@caugner.de>

* Update kumascript/macros/CSSSyntax.ejs

Co-authored-by: Claas Augner <github@caugner.de>

* Update kumascript/macros/CSSSyntax.ejs

Co-authored-by: Claas Augner <github@caugner.de>

* Update kumascript/macros/CSSSyntax.ejs

Co-authored-by: Claas Augner <github@caugner.de>

* Update kumascript/macros/CSSSyntax.ejs

Co-authored-by: Claas Augner <github@caugner.de>

* Update kumascript/macros/CSSSyntax.ejs

Co-authored-by: Claas Augner <github@caugner.de>

* Update kumascript/macros/CSSSyntax.ejs

Co-authored-by: Claas Augner <github@caugner.de>

* Update kumascript/macros/CSSSyntax.ejs

Co-authored-by: Claas Augner <github@caugner.de>

* Review comments

* Use mdn.localString for human-readable strings

* Remove replaceAll polyfill

* Actually concaenate newValues onto values

* updated yarn.lock

Co-authored-by: Claas Augner <caugner@mozilla.com>
Co-authored-by: Claas Augner <github@caugner.de>