Copy-pasto in the ExecForeignDelete documentation

Hi,

While working on FDW DML pushdown, I ran into a copy-pasto in the
ExecForeignDelete documentation in fdwhandler.sgml:

     The data in the returned slot is used only if the <command>DELETE</>
     query has a <literal>RETURNING</> clause or the foreign table has
     an <literal>AFTER ROW</> trigger.  Triggers require all columns,
but the

I don't think the data is referenced by the AFTER ROW DELETE triggers.
Attached is a patch to fix that.  The patch also avoids adding an
unnecessary RETURNING clause to DELETE when deparsing a remote DELETE
statement in postgres_fdw.

I'll add this to the next CF.

Best regards,
Etsuro Fujita