docs: update exanple descriptions

Author: TobiTenno

README.md

@@ -4,5 +4,5 @@ A few examples of projects using Romcal.
 
 - [html-web-page](./html-web-page) – loading romcal in a HTML script tag (`iife`).
 - [react-app](./react-app) – a basic React application loading and displaying romcal data.
-- [rest-api-with-express](./rest-api-with-express) – a REST API using Node.js and Express, written as CommonJs (`cjs`).
+- [rest-api-with-express](./rest-api-with-express) – a REST API using Node.js and Express, written as ES Module (`esm`) (formerly cjs).
 - [rest-api-with-fastify](./rest-api-with-fastify) – a REST API using Node.js and Fastify, written as ES Module (`esm`).