func golang.org/x/text/language.MustParse

2 uses

	golang.org/x/text/language (current package)
		tags.go#L13: func MustParse(s string) Tag {

	golang.org/x/text/cases
		map.go#L43: 		tags = append(tags, language.MustParse(s))

The pages are generated with Golds v0.7.6. (GOOS=linux GOARCH=amd64)