feat: Allow creating an empty Params instance.

src/params.rs

@@ -63,7 +63,8 @@ enum ParamsKind<'k, 'v> {
 }
 
 impl<'k, 'v> Params<'k, 'v> {
-    pub(crate) fn new() -> Self {
+    /// Create an empty list of parameters.
+    pub fn new() -> Self {
         Self {
             kind: ParamsKind::Small([Param::EMPTY; 3], 0),
         }