Re: [PATCH] Add pretty-printed XML output option

Some very-very old, rusted memory told me that there was something in standard – and indeed, it seems it described an optional Feature X069, “XMLSerialize: INDENT” for XMLSERIALIZE. So probably pretty-printing should go there, to XMLSERIALIZE, to follow the standard?

Oracle also has an option for it in XMLSERIALIZE, although in a slightly different form, with ability to specify the number of spaces for indentation https://docs.oracle.com/database/121/SQLRF/functions268.htm#SQLRF06231.