Add "udev" to FAQ

scripts/docspregen.py

@@ -187,8 +187,7 @@ Packages
 .. warning::
     **Linux Users**:
 
-        * Install "udev" rules file `99-platformio-udev.rules <https://github.com/platformio/platformio-core/blob/develop/scripts/99-platformio-udev.rules>`_
-          (an instruction is located inside a file).
+        * Install "udev" rules :ref:`faq_udev_rules`
         * Raspberry Pi users, please read this article
           `Enable serial port on Raspberry Pi <https://hallard.me/enable-serial-port-on-raspberry-pi/>`__.
 """)