Make ESM named imports work in Node

[alcuadrado]

Importing slang from a native ESM module is pretty cumbersome in Node right now. Here's an example of an error you may get if you try to use a normal named import:

% node index.mjs
file:///private/tmp/npmproject-4/index.mjs:6
import { ProductionKind } from "@nomicfoundation/slang/syntax/parser/index.js";
         ^^^^^^^^^^^^^^
SyntaxError: Named export 'ProductionKind' not found. The requested module '@nomicfoundation/slang/syntax/parser/index.js' is a CommonJS module, which may not support all module.exports as named exports.
CommonJS modules can always be imported via the default export, for example using:

import pkg from '@nomicfoundation/slang/syntax/parser/index.js';
const { ProductionKind } = pkg;

    at ModuleJob._instantiate (node:internal/modules/esm/module_job:124:21)
    at async ModuleJob.run (node:internal/modules/esm/module_job:190:5)

Node.js v18.16.1

This PR changes how we export things in JavaScript so that named imports from ESM modules work in Node.js.

The difference is really subtle and may be hard to understand at first glance, so here's an explanation:

• CJS and ESM aren't really compatible, but Node implements a compatibility mode which is not fully transparent.
• One of the things that is not transparent is the default export, as that doesn't exist in CJS.
• The compatibility layer hence treats reassigning module.exports as a default exports, hoping that it was the original intention of the author. That leads to named imports from ESM not working if you reassign it.
• If you keep the original module.exports and just add properties to it, those are treated as named exports.

[changeset-bot]

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Latest commit: 4a15766

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[OmarTawfik]

Thank you for catching this!