[BUG] Generated import for a custom error does not work in ESM mode

[FredTreg]

Describe the bug This is a follow-up of https://github.com/GoogleFeud/ts-runtime-checks/issues/47

ts-runtime-checks now properly generates an import statement for custom errors but does not generate the required .js extension when the project is in ESM mode (i.e. "type": "module")

The generated code then fails with:

node:internal/modules/esm/resolve:255
     throw new ERR_MODULE_NOT_FOUND(
           ^

Error [ERR_MODULE_NOT_FOUND]: Cannot find module '/server/dist/utils/errors' imported from /server/dist/modules/trails/trail.controller.js

Expected behavior For a project with "type": "module" defined in its package.json file, the following code should be generated:

import { InputError } from "../../utils/errors.js";

for now the following is generated (no .js extension):

import { InputError } from "../../utils/errors";

Additional context

• TypeScript 5.4.2
• ts-runtime-checks 0.5.0
• I could not find a workaround: forcing the import of the custom error would result in a duplicate import