doc: Mention timezone(zone, time) in section for AT TIME ZONE

timezone(zone, timestamp) is already mentioned as an equivalent of the
two first patterns in the table describing the AT TIME ZONE variants,
but did not mention the third case about "time" and its equivalent as an
SQL function, so let's be consistent here.

Extracted from a larger patch by the same author.

Author: Vik Fearing
Discussion: https://postgr.es/m/8e25dec4-5667-c1a5-6581-167d710c2182@postgresfriends.org

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d699451635fa74a33699e7c4d3d06a83..0769824e46b0c266e793fce08728165e5dab8347 100644 (file)
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -10738,6 +10738,13 @@ SELECT TIMESTAMP '2001-02-16 20:38:40' AT TIME ZONE 'Asia/Tokyo' AT TIME ZONE 'A
     <literal><replaceable>timestamp</replaceable> AT TIME ZONE
     <replaceable>zone</replaceable></literal>.
    </para>
+
+   <para>
+    The function <literal><function>timezone</function>(<replaceable>zone</replaceable>,
+    <replaceable>time</replaceable>)</literal> is equivalent to the SQL-conforming construct
+    <literal><replaceable>time</replaceable> AT TIME ZONE
+    <replaceable>zone</replaceable></literal>.
+   </para>
   </sect2>
 
   <sect2 id="functions-datetime-current">