doc: Fix the Doxygen section endings

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
diff --git a/src/conv.c b/src/conv.c
index ac39e29..ebc3eda 100644
--- a/src/conv.c
+++ b/src/conv.c
@@ -628,4 +628,4 @@
 	return rv;
 }
 
-/*! }@ */
+/*! @} */