Switch to side-by-side view

--- a/doc/upmpdcli.txt
+++ b/doc/upmpdcli.txt
@@ -190,6 +190,7 @@
 [[upmpdcli.configfile]]
 include::upmpdcli-config.txt[]
 
+[[radio-definitions]]
 === Radio station definitions
 
 Recent Upmpdcli versions (after 0.13) implement an OpenHome Radio service