Doc: add example of round(v, s) with negative s.

This has always worked, but you'd be unlikely to guess it
from the documentation.  Add an example showing it.

Lack of docs noted by David Johnston.  Back-patch to v13;
the documentation layout we used before that was not very
amenable to squeezing in multiple examples.

Discussion: https://postgr.es/m/CAKFQuwZ4Vy1Xty0G5Ok+ot=NDrU3C6hzF1JwUk-FEkwe3V9_RA@mail.gmail.com

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 22204f16c20c80f106d4ae94b0d30a99b2d33f83..2052d3c84452cd5ea5745cbe1eb1fd83b6930635 100644 (file)
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -1598,6 +1598,10 @@ repeat('Pg', 4) <returnvalue>PgPgPgPg</returnvalue>
        <para>
         <literal>round(42.4382, 2)</literal>
         <returnvalue>42.44</returnvalue>
+       </para>
+       <para>
+        <literal>round(1234.56, -1)</literal>
+        <returnvalue>1230</returnvalue>
        </para></entry>
       </row>