doc: Fix the Doxygen section endings

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
diff --git a/src/vty/telnet_interface.c b/src/vty/telnet_interface.c
index 001b016..7712041 100644
--- a/src/vty/telnet_interface.c
+++ b/src/vty/telnet_interface.c
@@ -220,4 +220,4 @@
 	talloc_free(tall_telnet_ctx);
 }
 
-/*! }@ */
+/*! @} */