doxygen: split VTY configuration in multiple files
diff --git a/include/osmocom/vty/telnet_interface.h b/include/osmocom/vty/telnet_interface.h
index c776f51..9a7c9e5 100644
--- a/include/osmocom/vty/telnet_interface.h
+++ b/include/osmocom/vty/telnet_interface.h
@@ -26,7 +26,7 @@
 
 #include <osmocom/vty/vty.h>
 
-/*! \addtogroup vty
+/*! \defgroup telnet_interface Telnet Interface
  *  @{
  */