Add new line

so that the list is styled correctly on website

docs/api/desktop-capturer.md

@@ -65,6 +65,7 @@ Starts a request to get all desktop sources, `callback` will be called with
 
 The `sources` is an array of `Source` objects, each `Source` represents a
 captured screen or individual window, and has following properties:
+
 * `id` String - The id of the captured window or screen used in
   `navigator.webkitGetUserMedia`. The format looks like `window:XX` or
   `screen:XX` where `XX` is a random generated number.