Add ".es" to recognised ECMAScript extensions

* Add ".es" to recognised JavaScript extensions
* Add heuristic to differentiate Erlang from ECMAScript
* Add test-case for .es heuristic

samples/JavaScript/axios.es

@@ -0,0 +1,13 @@
+import axios from "axios";
+
+export default {
+	async getIndex(prefix) {
+		const {data} = await axios.get((prefix || "") + "/index.json");
+		return data;
+	},
+	
+	async getContent(path, prefix) {
+		const {data} = await axios.get((prefix || "") + "/" + path + ".json");
+		return data;
+	}
+}