Doc: Further fix CREATE FOREIGN TABLE synopsis.
This patch fixes the partitioning synopsis in the Parameters section in
the CREATE FOREIGN TABLE documentation.  Follow-up for commit
Back-patch to v11 where default partition was introduced.
Discussion:
@@ -173,7 +173,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
</varlistentry>
<varlistentry>
- <term><literal>PARTITION OF <replaceable>parent_table</replaceable> FOR VALUES <replaceable class="parameter">partition_bound_spec</replaceable></literal></term>
+ <term><literal>PARTITION OF <replaceable>parent_table</replaceable> { FOR VALUES <replaceable class="parameter">partition_bound_spec</replaceable> | DEFAULT }</literal></term>
<listitem>
<para>
This form can be used to create the foreign table as partition of
