feat: add rule no-unnormalized-keys

[bmeck]

Prerequisites checklist

• I have read the contributing guidelines.

What is the purpose of this pull request?

To add a rule to check for JSON keys that are not normalized.

What changes did you make? (Give an overview)

Added a rule to check for JSON keys that are not normalized.

Related Issues

Fixes #32

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

Couldn't get options working on invalid test cases?

[mdjermanovic]

Can you add the rule to the plugin (otherwise, it could not be used):

json/src/index.js

Lines 29 to 32 in cac8847

	rules: {
	"no-duplicate-keys": noDuplicateKeys,
	"no-empty-keys": noEmptyKeys,
	},

And, also add it to the docs:

json/README.md

Lines 153 to 156 in cac8847

	## Rules
	- `no-duplicate-keys` - warns when there are two keys in an object with the same text.
	- `no-empty-keys` - warns when there is a key in an object that is an empty string or contains only whitespace (note: `package-lock.json` uses empty keys intentionally)

[mdjermanovic]

Suggested change

	* @fileoverview Tests for no-empty-keys rule.
	* @fileoverview Tests for no-unnormalized-keys rule.

[mdjermanovic]

Suggested change

	schema: {
	type: "array",
	minItems: 0,
	maxItems: 1,
	items: {
	enum: ["NFC", "NFD", "NFKC", "NFKD"],
	},
	},
	schema: [
	{
	enum: ["NFC", "NFD", "NFKC", "NFKD"],
	},
	],

This can be simplified by using the shorthand form (https://eslint.org/docs/latest/extend/custom-rules#options-schemas, the first format).

[mdjermanovic]

Can you add an invalid test where node.name is an Identifier node?