Update AuthorizeEndpointRequest.cs documentation (#404)

Line 63: changed documentation from "scope" to "state" to accurately reflect property

src/Microsoft.Owin.Security.OAuth/Messages/AuthorizeEndpointRequest.cs

@@ -60,7 +60,7 @@ public AuthorizeEndpointRequest(IReadableStringCollection parameters)
         public IList<string> Scope { get; private set; }
 
         /// <summary>
-        /// The "scope" query string parameter of the Authorize request. May be absent if the client does not require state to be 
+        /// The "state" query string parameter of the Authorize request. May be absent if the client does not require state to be 
         /// included when returning to the RedirectUri.
         /// </summary>
         public string State { get; set; }