translate static method
Translates a TextXValidationRule into a localized error message using the registered translation function.
If no translation function is registered for a specific rule type, it falls back to the rule's defaultMessage.
Implementation
static String translate(TextXValidationRule rule) =>
_map[rule.runtimeType.toString()] == null
? rule.defaultMessage
: _map[rule.runtimeType.toString()]!(rule);