Implement class regex for custom class name

[snorreks]

We are using clsx in our project and with tailwind we could use

	"tailwindCSS.experimental.classRegex": [
		["clsx\\(([^)]*)\\)", "(?:'|\"|`)([^']*)(?:'|\"|`)"]
	],

in settings.json to get intellisense.

It would be great if windi can also implement this.

[HiggsWRX]

+1. This would also be a desired feature for us