format.go
func NewSeededFormats(seeds []knownFormat, normalizer NameNormalizer) Registry {
	if normalizer == nil {
		normalizer = DefaultNameNormalizer
	}
	// copy here, don't modify original
	d := append([]knownFormat(nil), seeds...)
	return &defaultFormats{
		data:          d,
		normalizeName: normalizer,
	}
}
func NewSeededFormats(seeds []knownFormat, normalizer NameNormalizer) Registry {
	if normalizer == nil {
		normalizer = DefaultNameNormalizer
	}
	// copy here, don't modify original
	d := append([]knownFormat(nil), seeds...)
	return &defaultFormats{
		data:          d,
		normalizeName: normalizer,
	}
}
// NewSeededFormats creates a new formats registry