pgsql: Fix erroneous documentation of the syntax of CREATE CONSTRAINT T

Fix erroneous documentation of the syntax of CREATE CONSTRAINT TRIGGER.

The grammar requires a specific ordering of the clauses, but the
documentation showed a different order.  This error was introduced in
commit b47953f9c69d48a9261bd643e3170017b93f6337, which merged the CREATE
CONSTRAINT TRIGGER documentation into the CREATE TRIGGER page.  There is
no code bug AFAICS.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/2f6c8453cf3f38a70adbcb59489630cd5be92570

Modified Files
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doc/src/sgml/ref/create_trigger.sgml |    7 ++++---
1 files changed, 4 insertions(+), 3 deletions(-)