feat: support Auslan, mapping to en-AU CLDR data

locale.go

@@ -125,6 +125,9 @@ func getFallbackTag(tag language.Tag) (language.Tag, error) {
 	case "ase":
 		// there is no CLDR locale for American Sign Language, so we need to fall back to en-US
 		return language.AmericanEnglish, nil
+	case "asf":
+		// Australian Sign Language (Auslan)
+		return language.Make("en-AU"), nil
 	case "ht":
 		// Haitian Creole is simply not part of CLDR, as of 2023-01-23. This is very surprising.
 		return language.Make("fr-HT"), nil

locale_test.go

@@ -160,13 +160,27 @@ func TestGetLocaleData(t *testing.T) {
 	ta.NoError(err)
 	ta.Equal(language.AmericanEnglish, language.MustParse(l.Locale))
 
+	tag, err = language.Parse("asf")
+	ta.NoError(err)
+	ta.Equal("asf", tag.String())
+	l, err = localizer.GetLocaleData(tag)
+	ta.NoError(err)
+	ta.Equal("en-AU", language.MustParse(l.Locale).String())
+
 	tag, err = language.Parse("jam")
 	ta.NoError(err)
 	ta.Equal("jam", tag.String())
 	l, err = localizer.GetLocaleData(tag)
 	ta.NoError(err)
 	ta.Equal(language.English, language.MustParse(l.Locale))
 
+	tag, err = language.Parse("ht")
+	ta.NoError(err)
+	ta.Equal("ht", tag.String())
+	l, err = localizer.GetLocaleData(tag)
+	ta.NoError(err)
+	ta.Equal("fr-HT", language.MustParse(l.Locale).String())
+
 	tag, err = language.Parse("ca-valencia")
 	ta.NoError(err)
 	ta.Equal("ca-valencia", tag.String())