RegexModel.lettersOnly constructor
Only letters (any language), plus allowList groups and allow
characters: RegexModel.lettersOnly(allowList: [RegexChar.whitespace]).
Implementation
factory RegexModel.lettersOnly({
List<RegexChar> allowList = const [],
String allow = '',
String? title,
}) => RegexModel.allowOnly(
[RegexChar.letters, ...allowList],
allow: allow,
title: title,
);