rcu-tasks: Fix synchronize_rcu_tasks_trace() header comment

The synchronize_rcu_tasks_trace() header comment incorrectly claims that
any number of things delimit RCU Tasks Trace read-side critical sections,
when in fact only rcu_read_lock_trace() and rcu_read_unlock_trace() do so.
This commit therefore fixes this comment, and, while in the area, fixes
a typo in the rcu_read_lock_trace() header comment.

Reported-by: Alexei Starovoitov <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
diff --git a/include/linux/rcupdate_trace.h b/include/linux/rcupdate_trace.h
index 4c25a41..d9015aa 100644
--- a/include/linux/rcupdate_trace.h
+++ b/include/linux/rcupdate_trace.h
@@ -36,8 +36,8 @@ void rcu_read_unlock_trace_special(struct task_struct *t, int nesting);
 /**
  * rcu_read_lock_trace - mark beginning of RCU-trace read-side critical section
  *
- * When synchronize_rcu_trace() is invoked by one task, then that task
- * is guaranteed to block until all other tasks exit their read-side
+ * When synchronize_rcu_tasks_trace() is invoked by one task, then that
+ * task is guaranteed to block until all other tasks exit their read-side
  * critical sections.  Similarly, if call_rcu_trace() is invoked on one
  * task while other tasks are within RCU read-side critical sections,
  * invocation of the corresponding RCU callback is deferred until after