[fix] limiter.toml: botdetection.ip_limit turn off link_token by default

To activate the ``link_token`` method in the ``ip_limit`` method add the
following to your ``/etc/searxng/limiter.toml``::

   [botdetection.ip_limit]
   link_token = true

Related: https://github.com/searxng/searxng/pull/2357#issuecomment-1554116941


Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>