update example, tweak test

Author: Peter J. Herrel

features/menu-location.feature

@@ -44,7 +44,12 @@ Feature: Manage WordPress menu locations
       """
 
     When I run `wp menu location assign secondary-menu primary`
-    And I run `wp menu list --fields=slug,locations`
+    Then STDOUT should be:
+      """
+      Success: Assigned location primary to menu secondary-menu.
+      """
+
+    When I run `wp menu list --fields=slug,locations`
     Then STDOUT should be a table containing rows:
       | slug            | locations       |
       | primary-menu    |                 |

php/commands/menu-location.php

@@ -100,7 +100,7 @@ function($o) {
 	 * ## EXAMPLES
 	 *
 	 *     $ wp menu location assign primary-menu primary
-	 *     Success: Assigned location to menu.
+	 *     Success: Assigned location primary to menu primary-menu.
 	 *
 	 * @subcommand assign
 	 */