pgsql: Update PL documentation: An article at WebProNews quoted from

Log Message:
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Update PL documentation:

An article at WebProNews quoted from the PG docs as to the merits of
stored procedures. I have added a bit more material on their merits,
as well as making a few changes to improve the introductions to
PL/Perl and PL/Tcl.

Chris Browne

Modified Files:
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pgsql/doc/src/sgml:
plperl.sgml (r2.54 -> r2.55)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/plperl.sgml.diff?r1=2.54&r2=2.55)
plpgsql.sgml (r1.89 -> r1.90)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/plpgsql.sgml.diff?r1=1.89&r2=1.90)
pltcl.sgml (r2.40 -> r2.41)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/pltcl.sgml.diff?r1=2.40&r2=2.41)