Change description of 'state' object passed to ProgressUpdate (#3090)

* Change description of 'state' object passed to ProgressUpdate

Match description of the parameter to the description of the property on the event generated from the function call.

* fixed bad crefs

Author: jgscherber

xml/System.ComponentModel/BackgroundWorker.xml

@@ -750,7 +750,7 @@
       </Parameters>
       <Docs>
         <param name="percentProgress">The percentage, from 0 to 100, of the background operation that is complete.</param>
-        <param name="userState">The state object passed to <see cref="M:System.ComponentModel.BackgroundWorker.RunWorkerAsync(System.Object)" />.</param>
+        <param name="userState">A unique <see cref="T:System.Object"/> indicating the user state. Returned as the <see cref="P:System.ComponentModel.ProgressChangedEventArgs.UserState" /> property of the <see cref="T:System.ComponentModel.ProgressChangedEventArgs" />.</param>
         <summary>Raises the <see cref="E:System.ComponentModel.BackgroundWorker.ProgressChanged" /> event.</summary>
         <remarks>
           <format type="text/markdown"><![CDATA[