20230910 : add basic parser `CONST` rule, and add the grammar rule.

[uann] / .eslintrc.json

{
    "env": {
        "browser": true,
        "es2021": true
    },
    "extends": "standard-with-typescript",
    "parserOptions": {
        "ecmaVersion": "latest",
        "sourceType": "module"
    },
    "rules": {
    }
}