Encoding options are ignored for interface-valued slice elements #195

Encoding options work for typed slices but are ignored for the same values inside []interface{}:

v, _ := query.Values(struct {
    V []interface{} `url:",space,int"`
}{[]interface{}{true, false}})
fmt.Println(v.Get("V")) // true false; expected 1 0

A time.Time element similarly ignores a field's layout tag and uses fmt.Sprint instead.

Reproduced on current main with Go 1.27. I have a small fix that unwraps non-nil interfaces in valueString; both regressions failed first and the full tests now pass.