fix the spelling mistakes of comments

Hi, everyone

When reading the codes in file src/backend/replication/syncrep.c,
I have found two spelling mistakes of comments.

First
---------------------------------------------------------------------------------------------
/*-------------------------------------------------------------------------
*
* syncrep.c
*
* Synchronous replication is new as of PostgreSQL 9.1.
*
* If requested, transaction commits wait until their commit LSN are
* acknowledged by the synchronous standbys.
*
* This module contains the code for waiting and release★ of backends.
* All code in this module executes on the primary. The core streaming
* replication transport remains within WALreceiver/WALsender modules.
----------------------------------------------------------------------------------------------------
I think the word marked★ should be 'releasing'.

Second
-----------------------------------------------------------------------------------------------------------
/*
* Walk★ the specified queue from head. Set the state of any backends that
* need to be woken, remove them from the queue, and then wake them.
* Pass all = true to wake whole queue; otherwise, just wake up to
* the walsender's LSN.
*
* Must hold SyncRepLock.
*/
static int
SyncRepWakeQueue(bool all, int mode)
--------------------------------------------------------------------------------------------------------------
I think the word marked★ should be 'Wake'.

Attached patch fixed them.

--
以上
Liu Huailing
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Liu Huailing
Development Department III
Software Division II
Nanjing Fujitsu Nanda Software Tech. Co., Ltd.(FNST)
ADDR.: No.6 Wenzhu Road, Software Avenue,
Nanjing, 210012, China
TEL : +86+25-86630566-8439
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FAX : +86+25-83317685
MAIL : liuhuailing(at)cn(dot)fujitsu(dot)com
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