Returns a format mask for positive currency format.
Example of what can be returned:
$#,##0.00 (US on MacOS X)
$ #,##,##0.00 (India on MacOS X)
#,##0.00 $ (Icelandic on MacOS X)
Note that "$" symbol, "," symbol and "." symbols are only placeholders for the actual currency symbols that should be queried from the CurrencyFormatter class.