Correct representation of foreign tables in information schema

tables.table_type is supposed to be 'FOREIGN' rather than 'FOREIGN
TABLE' according to the SQL standard.

doc/src/sgml/information_schema.sgml

@@ -5456,7 +5456,7 @@ ORDER BY c.ordinal_position;
       <entry>
        Type of the table: <literal>BASE TABLE</literal> for a
        persistent base table (the normal table type),
-       <literal>VIEW</literal> for a view, <literal>FOREIGN TABLE</literal>
+       <literal>VIEW</literal> for a view, <literal>FOREIGN</literal>
        for a foreign table, or
        <literal>LOCAL TEMPORARY</literal> for a temporary table
       </entry>

src/backend/catalog/information_schema.sql

@@ -1914,7 +1914,7 @@ CREATE VIEW tables AS
              CASE WHEN nc.oid = pg_my_temp_schema() THEN 'LOCAL TEMPORARY'
                   WHEN c.relkind IN ('r', 'p') THEN 'BASE TABLE'
                   WHEN c.relkind = 'v' THEN 'VIEW'
-                  WHEN c.relkind = 'f' THEN 'FOREIGN TABLE'
+                  WHEN c.relkind = 'f' THEN 'FOREIGN'
                   ELSE null END
              AS character_data) AS table_type,