Fix typos in comments.

Backpatch to all supported versions, where applicable, to make backpatching
of future fixes go more smoothly.

Josh Soref

Discussion: https://www.postgresql.org/message-id/CACZqfqCf+5qRztLPgmmosr-B0Ye4srWzzw_mo4c_8_B_mtjmJQ@mail.gmail.com

src/backend/storage/ipc/latch.c

@@ -860,7 +860,7 @@ WaitEventAdjustWin32(WaitEventSet *set, WaitEvent *event)
  * reached.  At most nevents occurred events are returned.
  *
  * If timeout = -1, block until an event occurs; if 0, check sockets for
- * readiness, but don't block; if > 0, block for at most timeout miliseconds.
+ * readiness, but don't block; if > 0, block for at most timeout milliseconds.
  *
  * Returns the number of events occurred, or 0 if the timeout was reached.
  *

src/backend/storage/ipc/shm_mq.c

@@ -501,7 +501,7 @@ shm_mq_sendv(shm_mq_handle *mqh, shm_mq_iovec *iov, int iovcnt, bool nowait)
  * it will point to a temporary buffer.  This mostly avoids data copying in
  * the hoped-for case where messages are short compared to the buffer size,
  * while still allowing longer messages.  In either case, the return value
- * remains valid until the next receive operation is perfomed on the queue.
+ * remains valid until the next receive operation is performed on the queue.
  *
  * When nowait = false, we'll wait on our process latch when the ring buffer
  * is empty and we have not yet received a full message.  The sender will

src/backend/storage/ipc/standby.c

@@ -967,7 +967,7 @@ LogStandbySnapshot(void)
  * similar. We keep them separate because xl_xact_running_xacts is a
  * contiguous chunk of memory and never exists fully until it is assembled in
  * WAL. The inserted records are marked as not being important for durability,
- * to avoid triggering superflous checkpoint / archiving activity.
+ * to avoid triggering superfluous checkpoint / archiving activity.
  */
 static XLogRecPtr
 LogCurrentRunningXacts(RunningTransactions CurrRunningXacts)