pgsql: Update pg_ctl docs to explain server output behavior differences

Log Message:
-----------
Update pg_ctl docs to explain server output behavior differences on
win32 and non-win32 platforms.

Modified Files:
--------------
pgsql/doc/src/sgml/ref:
pg_ctl-ref.sgml (r1.50 -> r1.51)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/pg_ctl-ref.sgml?r1=1.50&r2=1.51)