Re: documentation structure

In, 0001-func.sgml-Consistently-use-optional-to-indicate-opti.patch

-<function>format</function>(<parameter>formatstr</parameter>
<type>text</type> [, <parameter>formatarg</parameter>
<type>"any"</type> [, ...] ])
+<function>format</function>(<parameter>formatstr</parameter>
<type>text</type> <optional>, <parameter>formatarg</parameter>
<type>"any"</type> [, ...] </optional>)

i change it further to
+<function>format</function>(<parameter>formatstr</parameter>
<type>text</type> <optional>, <parameter>formatarg</parameter>
<type>"any"</type> <optional>, ...</optional> </optional>)

i did these kind of change to <function>format</function>,
<function>concat_ws</function>, <function>concat</function>

I've rebased your patch,
added a commitfest entry: https://commitfest.postgresql.org/50/5278/
it seems I cannot mark you as the author in commitfest.
anyway, you ( Dagfinn Ilmari Mannsåker ) are the author of it.