Adding XYZOptions to objectliterals.jsdoc

I remain uncertain about when to use the @exportClass annotation and when to use the @exportSymbol.  osmsource.exports seems to get away with simply @exportSymbol, but many other sources use @exportProperty.

src/ol/source/xyzsource.js

@@ -1,5 +1,4 @@
 goog.provide('ol.source.XYZ');
-goog.provide('ol.source.XYZOptions');
 
 goog.require('ol.Attribution');
 goog.require('ol.Projection');
@@ -10,21 +9,6 @@ goog.require('ol.source.TileImage');
 goog.require('ol.tilegrid.XYZ');
 
 
-/**
- * @typedef {{attributions: (Array.<ol.Attribution>|undefined),
- *            crossOrigin: (string|undefined),
- *            extent: (ol.Extent|undefined),
- *            logo: (string|undefined),
- *            maxZoom: number,
- *            minZoom: (number|undefined),
- *            projection: (ol.Projection|undefined),
- *            tileUrlFunction: (ol.TileUrlFunctionType|undefined),
- *            url: (string|undefined),
- *            urls: (Array.<string>|undefined)}}
- */
-ol.source.XYZOptions;
-
-
 
 /**
  * @constructor