Fix many typos and inconsistencies

Author: Alexander Lakhin
Discussion: https://postgr.es/m/af27d1b3-a128-9d62-46e0-88f424397f44@gmail.com

src/backend/storage/buffer/freelist.c

@@ -220,7 +220,7 @@ StrategyGetBuffer(BufferAccessStrategy strategy, uint32 *buf_state)
 	 * If asked, we need to waken the bgwriter. Since we don't want to rely on
 	 * a spinlock for this we force a read from shared memory once, and then
 	 * set the latch based on that value. We need to go through that length
-	 * because otherwise bgprocno might be reset while/after we check because
+	 * because otherwise bgwprocno might be reset while/after we check because
 	 * the compiler might just reread from memory.
 	 *
 	 * This can possibly set the latch of the wrong process if the bgwriter

src/backend/storage/buffer/localbuf.c

@@ -537,7 +537,7 @@ GetLocalBufferStorage(void)
 /*
  * CheckForLocalBufferLeaks - ensure this backend holds no local buffer pins
  *
- * This is just like CheckBufferLeaks(), but for local buffers.
+ * This is just like CheckForBufferLeaks(), but for local buffers.
  */
 static void
 CheckForLocalBufferLeaks(void)

src/backend/storage/ipc/barrier.c

@@ -226,9 +226,9 @@ BarrierAttach(Barrier *barrier)
 }
 
 /*
- * Detach from a barrier.  This may release other waiters from BarrierWait and
- * advance the phase if they were only waiting for this backend.  Return true
- * if this participant was the last to detach.
+ * Detach from a barrier.  This may release other waiters from
+ * BarrierArriveAndWait() and advance the phase if they were only waiting for
+ * this backend.  Return true if this participant was the last to detach.
  */
 bool
 BarrierDetach(Barrier *barrier)