pgsql: Don't try aligning comments for new archive_command Win32 doc

Log Message:
-----------
Don't try aligning comments for new archive_command Win32 doc example;
it doesn't work.

Backpatch to 9.0.X.

Tags:
----
REL9_0_STABLE

Modified Files:
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pgsql/doc/src/sgml:
backup.sgml (r2.156.2.2 -> r2.156.2.3)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/backup.sgml?r1=2.156.2.2&r2=2.156.2.3)