Update README

README.md

@@ -155,12 +155,13 @@ Otherwise the following error message will be shown:
 ## nve(versionRange, args?, options?)
 
 _versionRange_: `string`<br> _args_: `string[]`<br> _options_:
-`object`<br>_Return value_: `object`
+`object`<br>_Return value_: `Promise<object>`
 
 `args` and `options` are the same as in
 [`child_process.spawn(command, args, options)`](https://nodejs.org/api/child_process.html#child_process_child_process_spawn_command_args_options).
 
-The return value is an object with the following properties:
+The return value is a promise resolving to an object with the following
+properties:
 
 - `promise`: resolves with
   [`code`](https://nodejs.org/api/child_process.html#child_process_event_exit)