pgsql: Rewrite discussion of string constant syntax to bring it into

Log Message:
-----------
Rewrite discussion of string constant syntax to bring it into line with
the politically correct view that backslash escapes are deprecated.

Modified Files:
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pgsql/doc/src/sgml:
syntax.sgml (r1.109 -> r1.110)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/syntax.sgml.diff?r1=1.109&r2=1.110)