pgsql: Deparse named arguments to use the new => operator instead of :=

Deparse named arguments to use the new => operator instead of :=

Tom Lane pointed out that this wasn't done, and asked whether that was
intentional.  Subsequent discussion was in favor of making the change,
so here we go.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/e044a44949c5b9c9f548e8a1cd4bf0b50fb2a1cc

Modified Files
--------------
src/backend/parser/parse_func.c            |    2 +-
src/backend/utils/adt/ruleutils.c          |    2 +-
src/test/regress/expected/polymorphism.out |   12 ++++++------
3 files changed, 8 insertions(+), 8 deletions(-)