A typo in backend/replication/README

Hi, I found a trivial typo in backend/replication/README

| Walreceiver IPC
| ---------------
|
| When the WAL replay in startup process has reached the end of archived WAL,
| recoverable using recovery_command, it starts up the walreceiver process

I think the recovery_command should be restore_command. This was
introduced at 9.0dev and all of REL9_x_STABLE contain this. I
don't know how "recoverable using restore_command" looks wired,
but I changed the sentsnce to fit the parameter name.

Likewise, the release note for 8.3.2 at HEAD(at)master contains the
similar typo. The typo originates in 8.4dev and back patched to
8.3.2 but I suspect that the all branches originates from 8.4dev
need to be fixed.

Patch 1: Fix for replication/README@@master
Patch 2: Fix for release-8(dot)3(dot)sgml(at)master

regards,

--
Kyotaro Horiguchi
NTT Open Source Software Center