Fix XML pretty printing.
Fix XML pretty printing.

Totally read the API docs wrong and missed that XML.prettyPrinting is
static, so I just added that to the document instead of changing things.

mathieuanthoine/flump,tconkling/flump,funkypandagame/flump,mathieuanthoine/flump,mathieuanthoine/flump,funkypandagame/flump,tconkling/flump