Maintain legacy RTOS behavior before mbed-5

Fork of mbed-rtos by mbed official

Revision:
123:58563e6cba1e
Parent:
112:53ace74b190c
--- a/rtos/Mutex.h	Wed Nov 09 12:22:14 2016 -0600
+++ b/rtos/Mutex.h	Mon Nov 14 17:14:42 2016 -0600
@@ -26,6 +26,8 @@
 #include "cmsis_os.h"
 
 namespace rtos {
+/** \addtogroup rtos */
+/** @{*/
 
 /** The Mutex class is used to synchronise the execution of threads.
  This is for example used to protect access to a shared resource.
@@ -67,3 +69,5 @@
 
 }
 #endif
+
+/** @}*/