doc: Fix the Doxygen section endings

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
diff --git a/include/osmocom/core/timer_compat.h b/include/osmocom/core/timer_compat.h
index 209e84a..d86c109 100644
--- a/include/osmocom/core/timer_compat.h
+++ b/include/osmocom/core/timer_compat.h
@@ -74,6 +74,6 @@
 #endif
 
 
-/*! }@ */
+/*! @} */
 
 #endif /* TIMER_COMPAT_H */