pgsql: Fix documentation reference to "above" example

Fix documentation reference to "above" example

found by Thom Brown

Branch
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REL9_0_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/39dbc62adedc8758580d099e4a21f1e5a4a0bf85

Modified Files
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doc/src/sgml/plpython.sgml | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)