Formatting currencies in the compact format fails for 1000 in locale nl_NL

[bartbroere]

I was formatting monetary amounts in the compact format with babel.numbers.format_compact_currency. Using the Dutch locale (nl_NL) I noticed that it failed for exactly one thousand euros. Add or remove a penny and it works again.

from babel.numbers import format_compact_currency

print(format_compact_currency(1000.01, 'EUR', locale='nl'))
# € 1K

print(format_compact_currency(1000, 'EUR', locale='nl'))
# Traceback (most recent call last):
#   File "/Users/bart/workspace/babel/reproduce_thousand_nl.py", line 6, in <module>
#     print(format_compact_currency(1000, 'EUR', locale='nl'))
#           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
#   File "/Users/bart/workspace/babel/babel/numbers.py", line 924, in format_compact_currency
#     number, format = _get_compact_format(number, compact_format, locale, fraction_digits)
#                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
#   File "/Users/bart/workspace/babel/babel/numbers.py", line 693, in _get_compact_format
#     format = compact_format[plural_form][str(magnitude)]
#              ~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
#   File "/Users/bart/workspace/babel/babel/localedata.py", line 264, in __getitem__
#     orig = val = self._data[key]
#                  ~~~~~~~~~~^^^^^
# KeyError: '1000'

After reproducing this, I also checked the locale nl, and nl_BE and those have the same issues.

I'm willing to contribute a fix, but people that are more familiar with the codebase might be able to do so quicker.