doc fix

libs/main/thread/pithreadpoolloop.cpp

@@ -25,6 +25,7 @@
 //! \addtogroup Thread
 //! \{
 //! \class PIThreadPoolLoop pithreadpoolloop.h
+//! \~\brief
 //! \~english Thread pool loop
 //! \~russian Пул потоков
 //!