The ConstTranslations class allows you to define the translations
as a const object, all at once. This is a little bit more efficient,
and also better for "hot reload", since a const variable
will respond to hot reloads, while final variables will not.
A Translations object is where you provide the translated strings.
Given a "translation-key", it returns a map of translations: { locale : translated strings }.
The translation-key may be the string itself that you want to translate, or an identifier.
The localize function localizes a "translatable string" to the given languageTag.
You must provide the key, which is usually the string you want to translate, and
also the translations object which holds the translations.
Use the localizeAllVersions method to return a Map of all translated strings,
where modifiers are the keys. In special, the unversioned text is indexed with
a null key.
The localizePlural function returns the translated version for the plural modifier.
After getting the version, substring %d will be replaced with the modifier.
The localizeVersion function localizes a "translatable string" to the given
languageTag. You must provide the key (which is usually the string you want to
translate), a modifier, and the translations object which holds the translations.
