Export of internal Abseil changes.

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87c9505f1d41b52486630ae4404b9060b89a6369 by Abseil Team <absl-team@google.com>:

Fix wording in a comment.

PiperOrigin-RevId: 214606367
GitOrigin-RevId: 87c9505f1d41b52486630ae4404b9060b89a6369
Change-Id: Icb95299b88e65840dfbc415b515412b24d578ce9

absl/synchronization/mutex.cc

@@ -1975,7 +1975,7 @@ void Mutex::LockSlowLoop(SynchWaitParams *waitp, int flags) {
 // Unlock this mutex, which is held by the current thread.
 // If waitp is non-zero, it must be the wait parameters for the current thread
 // which holds the lock but is not runnable because its condition is false
-// or it n the process of blocking on a condition variable; it must requeue
+// or it is in the process of blocking on a condition variable; it must requeue
 // itself on the mutex/condvar to wait for its condition to become true.
 void Mutex::UnlockSlow(SynchWaitParams *waitp) {
   intptr_t v = mu_.load(std::memory_order_relaxed);