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 f0155eef7f531fa7a1edee96aed7c3c8a38c4d7f..8f9035f008bde6aa26a59b86e7e34f2d2a432917 100644 (file)
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -1647,6 +1647,10 @@ repeat('Pg', 4) PgPgPgPg
        
         round(42.4382, 2)
         42.44
+       
+       
+        round(1234.56, -1)
+        1230