kernel/sem_wait.c : Add comment about semcount increasing awakened by signal or timeout
If a semaphore is awakened by signal or timeout, its semcount was increased from sem_waitirq.
In the sem_wait code, there is no mention about semcount restore, so added the description about this.
@@ -221,9 +221,8 @@ int sem_wait(FAR sem_t *sem)
* latter cases be examining the errno value.
*
* In the event that the semaphore wait was interrupted by a signal or
- * a timeout, certain semaphore clean-up operations have already been
- * performed (see sem_waitirq.c). Specifically:
- *
+ * a timeout, certain semaphore clean-up operations like semcount recovery
+ * have already been performed (see sem_waitirq.c). Specifically:
* - sem_canceled() was called to restore the priority of all threads
* that hold a reference to the semaphore,
* - The semaphore count was decremented, and
