No way to format percentages including decimals in `nl` locale

[tseaver]

In https://bugs.launchpad.net/zope.i18n/+bug/686058, @wichert reported:

In the nl locale percentages are always formatted without decimals:

>>> locale.numbers.getFormatter("percent").format(50.1)
'50%'

For most other things a locale can format you can use a 'long' length to get more information. No such luck here though:

>>> locale.numbers.getFormatter("percent", length="long").format(50.1)
KeyError: ('long',)