update/delete and execution-time partition pruning

We apparently forgot in 86dc90056df to remove a note in 5.11.4.
Partition Pruning saying this:

   <note>
    <para>
     Execution-time partition pruning currently only occurs for the
     <literal>Append</literal> and <literal>MergeAppend</literal> node types.
     It is not yet implemented for the <literal>ModifyTable</literal> node
     type, but that is likely to be changed in a future release of
     <productname>PostgreSQL</productname>.
    </para>
   </note>

Now because we include the Append/MergeAppend node even if the query
is update/delete, this note is no longer useful or valid.

Attached patch removes that note.

-- 
Amit Langote
EDB: http://www.enterprisedb.com