The CSRF error messages are not translated

[azmeuk]

flask-wtf/src/flask_wtf/csrf.py

Lines 99 to 115 in e9f085d

	if not data:
	raise ValidationError("The CSRF token is missing.")
	if field_name not in session:
	raise ValidationError("The CSRF session token is missing.")
	s = URLSafeTimedSerializer(secret_key, salt="wtf-csrf-token")
	try:
	token = s.loads(data, max_age=time_limit)
	except SignatureExpired as e:
	raise ValidationError("The CSRF token has expired.") from e
	except BadData as e:
	raise ValidationError("The CSRF token is invalid.") from e
	if not hmac.compare_digest(session[field_name], token):
	raise ValidationError("The CSRF tokens do not match.")

Even if those messages should not been seen that often, I do have users reporting that they encountered CSRF errors in production projects. For that reason, that would be nice if the messages be localized.

I suppose there is something to do with field.gettext but starting translating strings in flask-wtf would require to set up a whole i18n stack (catalogs, weblate etc.) like this is done in wtforms.