Split code into two snippets

cpp/freertos-active-object.md

@@ -53,7 +53,7 @@ private:
 
 ## Implementation for FreeRTOS
 
-Base class implementation:
+Thread safe queue implementation:
 
 ```cpp
 ///
@@ -150,7 +150,11 @@ public:
 private:
     QueueHandle_t mQueueHandle;
 };
+```
 
+Base class implementation:
+
+```cpp
 ///
 /// @brief Active object base class
 /// @details Use static polymorphism to avoid virtual function overhead