Issue #1085590 follow-up by Rob Loach, tim.plunkett: Add CHANGELOG.txt entry, fix typos.

core/CHANGELOG.txt

@@ -28,6 +28,7 @@ Drupal 8.0, xxxx-xx-xx (development version)
     * Support for generating and validating UUIDs.
 - JavaScript changes:
     * Updated to jQuery 1.7
+    * Updated to jQuery UI 1.9
 - Tremendously improved language support all around.
     * Great language improvements for users:
       * Improved language selection with user preference detection in the

core/modules/system/system.module

@@ -1526,7 +1526,7 @@ function system_library_info() {
     'website' => 'http://jqueryui.com/demos/position/',
     'version' => $libraries['jquery.ui.core']['version'],
     'js' => array(
-      'core/misc/ui/jquery.ui.position.min.js' => array(),
+      'core/misc/ui/ui/jquery.ui.position.min.js' => array(),
     ),
   );
   $libraries['jquery.ui.progressbar'] = array(
@@ -1657,7 +1657,7 @@ function system_library_info() {
       'core/misc/ui/ui/jquery.ui.widget.js' => array('group' => JS_LIBRARY, 'weight' => -10),
     ),
     'dependencies' => array(
-      array('system', 'ui'),
+      array('system', 'jquery.ui.core'),
     ),
   );
   $libraries['jquery.effects.core'] = array(