doc: Fix incorrect description of INCLUDING COMMENTS in CREATE FOREIGN TABLE.

Commit 302cf15759 added support for LIKE in CREATE FOREIGN TABLE.
In this feature, since indexes are not created for foreign tables,
comments on indexes are not copied either.

However, the documentation incorrectly stated that index comments
would be copied when using INCLUDING COMMENTS. This commit
corrects that by removing the mention of index comments.

Author: Fujii Masao <masao.fujii@gmail.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/f86cd84f-a6a3-4451-bae7-5cca9e63b06d@oss.nttdata.com

doc/src/sgml/ref/create_foreign_table.sgml

@@ -232,7 +232,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
         <term><literal>INCLUDING COMMENTS</literal></term>
         <listitem>
          <para>
-          Comments for the copied columns, constraints, and indexes will be
+          Comments for the copied columns and constraints will be
           copied.  The default behavior is to exclude comments, resulting in
           the copied columns and constraints in the new table having no
           comments.