update the JavaScript version policy to ES2023 (after June 2028)

[erwindon]

Is your feature request related to a problem? Please describe.
Start using features from this JS version

Describe the solution you'd like
Start using useful features from this JS version.

The 14th edition, ECMAScript 2023, was published in June 2023. This version introduces the toSorted, toReversed, with, findLast, and findLastIndex methods on Array.prototype and TypedArray.prototype, as well as the toSpliced method on Array.prototype; added support for #! shebang comments at the beginning of files to better facilitate executable ECMAScript files; and allowed the use of most Symbols as keys in weak collections.

Additional context
Update:

• docs/README.md (ecmaVersion)
• eslint.config.js
• any JS code