fix comment

include/realtime_tools/realtime_helpers.hpp

@@ -62,7 +62,7 @@ bool configure_sched_fifo(int priority);
  * will not swap out the pages to disk i.e., the pages are guaranteed to stay in
  * RAM until later unlocked - which is important for realtime applications.
  * \param[out] message a message describing the result of the operation
- * \returns  a pair of a boolean indicating whether the operation succeeded or not.
+ * \returns true if memory locking succeeded, false otherwise.
 */
 
 [[deprecated("Use std::pair<bool, std::string> lock_memory() instead.")]]