Add support for the "scale" stem to formatted numbers

[jwarby]

Which package?
intl-messageformat-parser

Is your feature request related to a problem? Please describe.
I'd like to pass an object with some percentage values to a formatted message which is using the percent option. The values are already scaled appropriately, eg value: 25.67 for 25.67%, but percent will multiply the value by 100.

Describe the solution you'd like
To be able to use the scale/dddd stem in number skeletons, eg {value, number, ::percent scale/0.1}

Describe alternatives you've considered
Our current workaround is to add a special case for percentage values and divide them by 100 before passing them to the formatting component.

Additional context
Add any other context or screenshots about the feature request here.

[jwarby]

Thanks for this @longlho!