qapi: Drop stray Arguments: line from qmp_capabilities docs

Reported-by: John Snow <jsnow@redhat.com>
Fixes: 119ebac (qapi-schema: use generated marshaller for 'qmp_capabilities')
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240322140910.328840-2-armbru@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>

qapi/control.json

@@ -11,8 +11,6 @@
 #
 # Enable QMP capabilities.
 #
-# Arguments:
-#
 # @enable: An optional list of QMPCapability values to enable.  The
 #     client must not enable any capability that is not mentioned in
 #     the QMP greeting message.  If the field is not provided, it