pgsql: Correct ALTER TYPE -> SET DATA TYPE in ALTER TABLE documentation

Correct ALTER TYPE -> SET DATA TYPE in ALTER TABLE documentation.

The latter is the correct name of the operation to change the data type
of a column.

Noah Misch

Branch
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REL9_0_STABLE

Details
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http://git.postgresql.org/gitweb?p=postgresql.git;a=commitdiff;h=2c3e29299842f6de74ff96d35ecaa1cc98fbcd5d

Modified Files
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doc/src/sgml/ref/alter_table.sgml |    8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)