8028283: Revert JavaDoc changes pushed for JDK-7068423

Reviewed-by: art, serb

src/share/classes/java/awt/GraphicsDevice.java

@@ -341,12 +341,11 @@ public abstract class GraphicsDevice {
     }
 
     /**
-     * Returns the {@code Window} object representing the
+     * Returns the <code>Window</code> object representing the
      * full-screen window if the device is in full-screen mode.
      *
-     * @return the full-screen window, or {@code null} if the device is
-     * not in full-screen mode. The {@code Window} object can differ
-     * from the object previously set by {@code setFullScreenWindow}.
+     * @return the full-screen window, or <code>null</code> if the device is
+     * not in full-screen mode.
      * @see #setFullScreenWindow(Window)
      * @since 1.4
      */