Add support for the other html template types

cast_test.go

@@ -50,6 +50,9 @@ func TestToString(t *testing.T) {
 	assert.Equal(t, ToString([]byte("one time")), "one time")
 	assert.Equal(t, ToString(template.HTML("one time")), "one time")
 	assert.Equal(t, ToString(template.URL("http://somehost.foo")), "http://somehost.foo")
+	assert.Equal(t, ToString(template.JS("(1+2)")), "(1+2)")
+	assert.Equal(t, ToString(template.CSS("a")), "a")
+	assert.Equal(t, ToString(template.HTMLAttr("a")), "a")
 	assert.Equal(t, ToString(foo), "one more time")
 	assert.Equal(t, ToString(nil), "")
 	assert.Equal(t, ToString(true), "true")

caste.go

@@ -244,6 +244,12 @@ func ToStringE(i interface{}) (string, error) {
 		return string(s), nil
 	case template.URL:
 		return string(s), nil
+	case template.JS:
+		return string(s), nil
+	case template.CSS:
+		return string(s), nil
+	case template.HTMLAttr:
+		return string(s), nil
 	case nil:
 		return "", nil
 	case fmt.Stringer: