doxygen: split VTY configuration in multiple files
diff --git a/src/vty/telnet_interface.c b/src/vty/telnet_interface.c
index 89cba58..ed64cda 100644
--- a/src/vty/telnet_interface.c
+++ b/src/vty/telnet_interface.c
@@ -33,7 +33,7 @@
 #include <osmocom/vty/buffer.h>
 #include <osmocom/vty/command.h>
 
-/*! \addtogroup vty
+/*! \addtogroup telnet_interface
  *  @{
  */
 /*! \file telnet_interface.c */