Support CNI 1.0.0

Fix #792

vendor/golang.org/x/text/language/language.go

@@ -412,6 +412,10 @@ func (t Tag) Extensions() []Extension {
 // are of the allowed values defined for the Unicode locale extension ('u') in
 // https://www.unicode.org/reports/tr35/#Unicode_Language_and_Locale_Identifiers.
 // TypeForKey will traverse the inheritance chain to get the correct value.
+//
+// If there are multiple types associated with a key, only the first will be
+// returned. If there is no type associated with a key, it returns the empty
+// string.
 func (t Tag) TypeForKey(key string) string {
 	if !compact.Tag(t).MayHaveExtensions() {
 		if key != "rg" && key != "va" {