pgsql: Re-add documentation for --no-readline option of psql, mistakenly

Log Message:
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Re-add documentation for --no-readline option of psql, mistakenly removed a decade ago. Backpatch to release 7.4.

Tags:
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REL8_4_STABLE

Modified Files:
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pgsql/doc/src/sgml/ref:
psql-ref.sgml (r1.225.2.1 -> r1.225.2.2)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/psql-ref.sgml?r1=1.225.2.1&r2=1.225.2.2)