doc: remove incorrectly duplicated piece of text

doc/reference.rst

@@ -172,15 +172,6 @@ Default value: ``off`` (wait for zones to be loaded before answering)
 user
 ^^^^
 
-System ``user`` or ``user``.``group`` under which the Knot DNS is run
-after starting and binding to interfaces.  Linux capabilities
-(:ref:`Required libraries`) are employed if supported and this
-
-.. _user:
-
-user
-^^^^
-
 System ``user`` or ``user``.``group`` under which the Knot DNS is run
 after starting and binding to interfaces.  Linux capabilities
 (:ref:`Required libraries`) are employed if supported and this