Fix various typos and grammar errors in comments.

Author: Dmitriy Olshevskiy
Discussion: 553D00A6.4090205@bk.ru

src/backend/access/brin/brin_tuple.c

@@ -304,7 +304,7 @@ brin_free_tuple(BrinTuple *tuple)
 }
 
 /*
- * Create an palloc'd copy of a BrinTuple.
+ * Create a palloc'd copy of a BrinTuple.
  */
 BrinTuple *
 brin_copy_tuple(BrinTuple *tuple, Size len)

src/backend/access/nbtree/nbtree.c

@@ -40,7 +40,7 @@ typedef struct
 	BTSpool    *spool;
 
 	/*
-	 * spool2 is needed only when the index is an unique index. Dead tuples
+	 * spool2 is needed only when the index is a unique index. Dead tuples
 	 * are put into spool2 instead of spool in order to avoid uniqueness
 	 * check.
 	 */

src/backend/access/transam/twophase.c

@@ -291,7 +291,7 @@ AtAbort_Twophase(void)
 }
 
 /*
- * This is called after we have finished transfering state to the prepared
+ * This is called after we have finished transferring state to the prepared
  * PGXACT entry.
  */
 void

src/backend/catalog/objectaddress.c

@@ -100,7 +100,7 @@ typedef struct
 	AclObjectKind acl_kind;		/* ACL_KIND_* of this object type */
 	bool		is_nsp_name_unique;		/* can the nsp/name combination (or
 										 * name alone, if there's no
-										 * namespace) be considered an unique
+										 * namespace) be considered a unique
 										 * identifier for an object of this
 										 * class? */
 } ObjectPropertyType;
@@ -3241,7 +3241,7 @@ pg_identify_object(PG_FUNCTION_ARGS)
 
 			/*
 			 * We only return the object name if it can be used (together with
-			 * the schema name, if any) as an unique identifier.
+			 * the schema name, if any) as a unique identifier.
 			 */
 			if (get_object_namensp_unique(address.classId))
 			{

src/backend/commands/indexcmds.c

@@ -1051,7 +1051,7 @@ ComputeIndexAttrs(IndexInfo *indexInfo,
 				 */
 
 				/*
-				 * A expression using mutable functions is probably wrong,
+				 * An expression using mutable functions is probably wrong,
 				 * since if you aren't going to get the same result for the
 				 * same data every time, it's not clear what the index entries
 				 * mean at all.

src/backend/executor/nodeModifyTable.c

@@ -304,7 +304,7 @@ ExecInsert(TupleTableSlot *slot,
 	 * inserting the record into the heap and all indexes.
 	 *
 	 * ExecWithCheckOptions will elog(ERROR) if a violation is found, so
-	 * the tuple will never be seen, if it violates the the WITH CHECK
+	 * the tuple will never be seen, if it violates the WITH CHECK
 	 * OPTION.
 	 *
 	 * ExecWithCheckOptions() will skip any WCOs which are not of

src/backend/postmaster/bgworker.c

@@ -130,7 +130,7 @@ BackgroundWorkerShmemInit(void)
 		/*
 		 * Copy contents of worker list into shared memory.  Record the shared
 		 * memory slot assigned to each worker.  This ensures a 1-to-1
-		 * correspondence betwen the postmaster's private list and the array
+		 * correspondence between the postmaster's private list and the array
 		 * in shared memory.
 		 */
 		slist_foreach(siter, &BackgroundWorkerList)

src/backend/replication/logical/snapbuild.c

@@ -1597,7 +1597,7 @@ SnapBuildSerialize(SnapBuild *builder, XLogRecPtr lsn)
 
 	/*
 	 * We may overwrite the work from some other backend, but that's ok, our
-	 * snapshot is valid as well, we'll just have done some superflous work.
+	 * snapshot is valid as well, we'll just have done some superfluous work.
 	 */
 	if (rename(tmppath, path) != 0)
 	{

src/backend/storage/lmgr/lwlock.c

@@ -848,7 +848,7 @@ LWLockDequeueSelf(LWLock *lock)
 
 		/*
 		 * Somebody else dequeued us and has or will wake us up. Deal with the
-		 * superflous absorption of a wakeup.
+		 * superfluous absorption of a wakeup.
 		 */
 
 		/*
@@ -1183,7 +1183,7 @@ LWLockAcquireOrWait(LWLock *lock, LWLockMode mode)
 		{
 			/*
 			 * Wait until awakened.  Like in LWLockAcquire, be prepared for bogus
-			 * wakups, because we share the semaphore with ProcWaitForSignal.
+			 * wakeups, because we share the semaphore with ProcWaitForSignal.
 			 */
 			LOG_LWDEBUG("LWLockAcquireOrWait", lock, "waiting");
 

src/backend/utils/cache/inval.c

@@ -516,7 +516,7 @@ RegisterRelcacheInvalidation(Oid dbId, Oid relId)
 /*
  * RegisterSnapshotInvalidation
  *
- * Register a invalidation event for MVCC scans against a given catalog.
+ * Register an invalidation event for MVCC scans against a given catalog.
  * Only needed for catalogs that don't have catcaches.
  */
 static void