pgsql: Simplify references to backslash-doubling in func.sgml.

Simplify references to backslash-doubling in func.sgml.

Several places were still written as though standard_conforming_strings
didn't exist, much less be the default. Now that it is on by default,
we can simplify the text and just insert occasional notes suggesting that
you might have to think harder if it's turned off. Per discussion of a
suggestion from Hannes Frederic Sowa.

Back-patch to 9.1 where standard_conforming_strings was made the default.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/a5c1a1969dd838189e5cc936c15cb40e13fb6d68

Modified Files
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doc/src/sgml/func.sgml | 41 ++++++++++++++++-------------------------
1 files changed, 16 insertions(+), 25 deletions(-)