typofix for prepare transaction page

Change "It's" to "Its", below.
Josh

diff --git a/doc/src/sgml/ref/prepare_transaction.sgml
b/doc/src/sgml/ref/prepare_transaction.sgml
index 6744dd6..261cedc 100644
*** a/doc/src/sgml/ref/prepare_transaction.sgml
--- b/doc/src/sgml/ref/prepare_transaction.sgml
*************** PREPARE TRANSACTION <replaceable class="
*** 84,90 ****

    <para>
     <command>PREPARE TRANSACTION</> is not intended for use in applications
!    or interactive sessions. It's purpose is to allow an external
     transaction manager to perform atomic global transactions across multiple
     databases or other transactional resources. Unless you're writing a
     transaction manager, you probably shouldn't be using <command>PREPARE
--- 84,90 ----

<para>
<command>PREPARE TRANSACTION</> is not intended for use in applications
! or interactive sessions. Its purpose is to allow an external
transaction manager to perform atomic global transactions across multiple
databases or other transactional resources. Unless you're writing a
transaction manager, you probably shouldn't be using <command>PREPARE