chore: enable eslint for css files

[SwetaTanwar]

Prerequisites checklist

• I have read the contributing guidelines.

What is the purpose of this pull request?

Enable linting CSS files, handy for test.css file for triaging issues & working on rules.

What changes did you make? (Give an overview)

Update ESLint config to lint CS files, it seems it was removed in #324

Related Issues

NA

Is there anything you'd like reviewers to focus on?

No

[lumirlumir]

Good Catch! I've left one comment on it.

---

Indeed, there was a configuration for css prior to #324.

Also, I used this feature when I worked on the CSS repository, and there's a test.css entry in .gitignore to verify it:

css/.gitignore

Line 62 in 17746f9

test.css

[lumirlumir]

Suggested change

	{
	name: "css/css",
	files: ["**/*.css"],
	language: "css/css",
	plugins: { css },
	extends: ["css/recommended"],
	},
	// This CSS configuration is mainly used to validate the `test.css` file for local testing.
	{
	name: "css/css",
	plugins: { css },
	files: ["**/*.css"],
	language: "css/css",
	extends: ["css/recommended"],
	},

Can we add a comment like above to ensure not to be removed in the future by mistake?

Also, as a non-blocking request, I think it would be nice if the property keys were ordered name -> plugins, like in the JSON configuration.