Minor typo in domain-mapping.php

This isn't a new bug, but figured I'd report it since I haven't seen it corrected in a few versions. In domain-mapping.php on line 37 it says:

// UnComment out the line below to allow multiple domain mappings per blog

This implies that this should be commented out by default, but it isn't. It makes sense that this is commented out by default because a minority of networks use multidomains.