tpl: Allow 'Querify' to take lone slice/interface argument

Querify can now take a lone string/interface slice (with string
keys) as a parameter, or multiple string parameters, to build
URL queries.

Querify earlier used 'Dictionary' to add key/value pairs to a
map to build URL queries. Changed to dynamically generate ordered
key/value pairs. Cannot take string slice as key (earlier
possible due to Dictionary).

Added tests and benchmarks for querify.

Closes #6735

tpl/collections/collections.go

@@ -424,13 +424,39 @@ func (ns *Namespace) Last(limit interface{}, seq interface{}) (interface{}, erro
 // Querify encodes the given parameters in URL-encoded form ("bar=baz&foo=quux") sorted by key.
 func (ns *Namespace) Querify(params ...interface{}) (string, error) {
 	qs := url.Values{}
-	vals, err := ns.Dictionary(params...)
-	if err != nil {
-		return "", errors.New("querify keys must be strings")
+
+	if len(params) == 1 {
+		switch v := params[0].(type) {
+		case []string:
+			if len(v)%2 != 0 {
+				return "", errors.New("invalid query")
+			}
+
+			for i := 0; i < len(v); i += 2 {
+				qs.Add(v[i], v[i+1])
+			}
+
+			return qs.Encode(), nil
+
+		case []interface{}:
+			params = v
+
+		default:
+			return "", errors.New("query keys must be strings")
+		}
 	}
 
-	for name, value := range vals {
-		qs.Add(name, fmt.Sprintf("%v", value))
+	if len(params)%2 != 0 {
+		return "", errors.New("invalid query")
+	}
+
+	for i := 0; i < len(params); i += 2 {
+		switch v := params[i].(type) {
+		case string:
+			qs.Add(v, fmt.Sprintf("%v", params[i+1]))
+		default:
+			return "", errors.New("query keys must be strings")
+		}
 	}
 
 	return qs.Encode(), nil