Fixed a long-standing documentation issue in qsched.c

src/qsched.c

@@ -507,7 +507,7 @@ void qsched_run_pthread ( struct qsched *s , int nr_threads , qsched_funtype fun
  *        task type and a pointer to the task data.
  *
  * Depending on what type of threads QuickSched was compiled with,
- * i.e. OpenMP and/or pthreads, and if the #qsched_flag_spin or
+ * i.e. OpenMP and/or pthreads, and if the #qsched_flag_yield or
  * #qsched_flag_pthread flags were set, this function calls
  * #qsched_run_openmp or #qsched_run_pthread respectively.
  */