pgsql: doc: Remove reference to views for TRUNCATE privilege

doc: Remove reference to views for TRUNCATE privilege

The page about privilege rights mentioned that TRUNCATE could be applied
to views or even other relation types.  This is confusing as this
command can be used only on tables and on partitioned tables.

Oversight in afc4a78.

Reported-by: Harisai Hari
Reviewed-by: Laurenz Albe
Discussion: https://postgr.es/m/161157636877.14625.15340884663716426087@wrigleys.postgresql.org
Backpatch-through: 12

Branch
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REL_12_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/d43e23505285b2f39dbda615d8cab51d0905fadc

Modified Files
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doc/src/sgml/ddl.sgml | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)