Pass util.inspect to custom inspect methods

[Jamesernator]

Currently when using [Symbol.for('nodejs.util.inspect.custom')](depth, opts) in cross-environment code we have a problem when wanting to use the results of util.inspect on inner values of our value.

For example consider an implementation of Complex like so:

class Complex {
 #real;
 #imag;

 constructor(real, imag) {
 this.#real = real;
 this.#imag = imag;
 }

 get real() {
 return this.#real;
 }

 get imag() {
 return this.#imag;
 }
}

If we wish to extend it with [Symbol.for('nodejs.util.custom.inspect')] we can do something like the following:

class Complex {
 // ...
 [Symbol.for('nodejs.util.inspect.custom')]() {
 return `Complex { real: ${ this.#real }, imag: ${ this.#imag } }`
 }
}

However this has the downside of losing the color-formatting on the numbers. In order to fix this we could import util.inspect and use it as follows:

import { inspect } from 'util';

class Complex {
 // ...
 [Symbol.for('nodejs.util.inspect.custom')]() {
 return `Complex { real: ${ inspect(this.#real) }, imag: ${ inspect(this.#imag) } }`
 }
}

However now we have made our code non-portable by importing util, even though this code has no other dependencies on Node.

As such I'd like to propose passing inspect into [Symbol.for('nodejs.util.inspect.custom')]() as the third argument so that we could write it like so:

class Complex {
 // ...
 [Symbol.for('nodejs.util.inspect.custom')](depth, opts, inspect) {
 return `Complex { real: ${ inspect(this.#real) }, imag: ${ inspect(this.#imag) } }`;
 }

[aduh95]

Do you want to submit a PR implementing this change?