Fix typo.

Source/Widgets/Viewer/Viewer.js

@@ -96,7 +96,7 @@ define([
      * @param {SkyBox} [options.skyBox] The skybox used to render the stars.  When <code>undefined</code>, the default stars are used.
      * @param {Element} [options.fullscreenElement=document.body] The element to make full screen when the full screen button is pressed.
      * @param {Boolean} [options.useDefaultRenderLoop=true] True if this widget should control the render loop, false otherwise.
-     * @param {Number} [options.targetFrameRate] The target frame rate when using the default render loot.
+     * @param {Number} [options.targetFrameRate] The target frame rate when using the default render loop.
      * @param {Boolean} [options.showRenderLoopErrors=true] If true, this widget will automatically display an HTML panel to the user containing the error, if a render loop error occurs.
      * @param {Boolean} [options.automaticallyTrackDataSourceClocks=true] If true, this widget will automatically track the clock settings of newly added DataSources, updating if the DataSource's clock changes.  Set this to false if you want to configure the clock independently.
      * @param {Object} [options.contextOptions=undefined] Context and WebGL creation properties corresponding to {@link Context#options}.