dispatcher: small spelling fix (bellow -> below)

src/modules/dispatcher/doc/dispatcher_admin.xml

@@ -1123,7 +1123,7 @@ modparam("dispatcher", "ds_db_extra_attrs", "socket=socket;pref=prefix")
 				used to control congestion tolerance. When facing congestion the weight of
 				a gateway is lowered by 1 for every ms of estimated congestion, a 'rweight'
 				value of 50 is recommended. See the example "configuring load balancing with
-				congestion detection" bellow.
+				congestion detection" below.
 				</para>
 				<para>
 				The congestion estimation is done using an EWMA (see ds_latency_estimator_alpha).