Remove .js suffix in require paths

Remove the .js suffix in require paths to make requires consistent
across the project.

lib/clusterTools/index.js

@@ -12,5 +12,5 @@ module.exports = ({config} = {}) => ({
 		arg1 is the instanceID
 		Promise resolves with a string, either the displayName or instanceID if not found.
 	*/
-	getInstanceName: require("./getInstanceName.js")(config),
+	getInstanceName: require("./getInstanceName")(config),
 })

lib/isFactorioCommand/index.js

@@ -1 +1 @@
-module.exports = require("./isFactorioCommand.js");
+module.exports = require("./isFactorioCommand");

lib/manager/modManager.js

@@ -36,7 +36,7 @@ modManager.listMods(config, instance);
 */
 async function listMods(config, instance) {
 	return new Promise((resolve, reject) => {
-		const instances = require("./../getInstances.js")(config).sync();
+		const instances = require("./../getInstances")(config).sync();
 		if (instances.includes(instance.name)) {
 			factorioAPI.init(false, instance.path("instanceMods"), instance.path("saves"), config.factorio_version);
 			factorioAPI.authenticate({