os: implement ExpandUnsignedValueToAscii
...
Nintendo does this as of latest firmware.
It's desirable because it removes the only usage of util::SNPrintf() from os library,
which means programs which don't otherwise use SNPrintf do not need to link it into .text.
This saves ~0xD40 of .text as of time-of-commit when successfully unlinking, and e.g.
reduces our sm (and other modules) memory size by a page.
Michael Scire
committed
on 29 Sep 2021