Fix more instances of "the the" in comments.

Plus one instance of "to to" in the docs.

doc/src/sgml/extend.sgml

@@ -1187,7 +1187,7 @@ include $(PGXS)
 
    <para>
     Alternatively, you can set up a directory for a VPATH build in a similar
-    way to how it is done for the core code. One way to to this is using the
+    way to how it is done for the core code. One way to do this is using the
     core script <filename>config/prep_buildtree</>. Once this has been done
     you can build by setting the <literal>make</literal> variable
     <varname>USE_VPATH</varname> like this:

src/backend/access/transam/xlog.c

@@ -424,9 +424,9 @@ typedef struct XLogCtlInsert
 	/*
 	 * CurrBytePos is the end of reserved WAL. The next record will be inserted
 	 * at that position. PrevBytePos is the start position of the previously
-	 * inserted (or rather, reserved) record - it is copied to the the prev-
-	 * link of the next record. These are stored as "usable byte positions"
-	 * rather than XLogRecPtrs (see XLogBytePosToRecPtr()).
+	 * inserted (or rather, reserved) record - it is copied to the prev-link
+	 * of the next record. These are stored as "usable byte positions" rather
+	 * than XLogRecPtrs (see XLogBytePosToRecPtr()).
 	 */
 	uint64		CurrBytePos;
 	uint64		PrevBytePos;
@@ -10831,7 +10831,7 @@ next_record_is_invalid:
  * 'tliRecPtr' is the position of the WAL record we're interested in. It is
  * used to decide which timeline to stream the requested WAL from.
  *
- * If the the record is not immediately available, the function returns false
+ * If the record is not immediately available, the function returns false
  * if we're not in standby mode. In standby mode, waits for it to become
  * available.
  *

src/backend/access/transam/xlogfuncs.c

@@ -589,7 +589,7 @@ pg_backup_start_time(PG_FUNCTION_ARGS)
 	}
 
 	/*
-	 * Parse the file to find the the START TIME line.
+	 * Parse the file to find the START TIME line.
 	 */
 	backup_start_time[0] = '\0';
 	while (fgets(fline, sizeof(fline), lfp) != NULL)

src/backend/commands/vacuum.c

@@ -382,7 +382,7 @@ get_rel_oids(Oid relid, const RangeVar *vacrel)
  *   DEAD or RECENTLY_DEAD (see HeapTupleSatisfiesVacuum).
  * - freezeLimit is the Xid below which all Xids are replaced by
  *   FrozenTransactionId during vacuum.
- * - xidFullScanLimit (computed from the the table_freeze_age parameter)
+ * - xidFullScanLimit (computed from table_freeze_age parameter)
  *   represents a minimum Xid value; a table whose relfrozenxid is older than
  *   this will have a full-table vacuum applied to it, to freeze tuples across
  *   the whole table.  Vacuuming a table younger than this value can use a

src/backend/replication/walreceiver.c

@@ -1152,7 +1152,7 @@ XLogWalRcvSendHSFeedback(bool immed)
 	elog(DEBUG2, "sending hot standby feedback xmin %u epoch %u",
 		 xmin, nextEpoch);
 
-	/* Construct the the message and send it. */
+	/* Construct the message and send it. */
 	resetStringInfo(&reply_message);
 	pq_sendbyte(&reply_message, 'h');
 	pq_sendint64(&reply_message, GetCurrentIntegerTimestamp());

src/backend/storage/ipc/procarray.c

@@ -662,7 +662,7 @@ ProcArrayApplyRecoveryInfo(RunningTransactions running)
 	pfree(xids);
 
 	/*
-	 * latestObservedXid is at least set to the the point where SUBTRANS was
+	 * latestObservedXid is at least set to the point where SUBTRANS was
 	 * started up to (c.f. ProcArrayInitRecovery()) or to the biggest xid
 	 * RecordKnownAssignedTransactionIds() was called for.  Initialize
 	 * subtrans from thereon, up to nextXid - 1.

src/backend/utils/cache/relcache.c

@@ -3837,7 +3837,7 @@ RelationGetIndexAttrBitmap(Relation relation, IndexAttrBitmapKind attrKind)
 {
 	Bitmapset  *indexattrs; /* indexed columns */
 	Bitmapset  *uindexattrs; /* columns in unique indexes */
-	Bitmapset  *idindexattrs; /* columns in the the replica identity */
+	Bitmapset  *idindexattrs; /* columns in the replica identity */
 	List	   *indexoidlist;
 	ListCell   *l;
 	MemoryContext oldcxt;

src/pl/plpgsql/src/pl_exec.c

@@ -6594,7 +6594,7 @@ format_expr_params(PLpgSQL_execstate *estate,
 
 /*
  * Return a formatted string with information about PreparedParamsData, or NULL
- * if the there are no parameters.
+ * if there are no parameters.
  */
 static char *
 format_preparedparamsdata(PLpgSQL_execstate *estate,