should be universal to all forms of arrays

[Ayana-chan]

Now serde_qs only support array like user_ids[0]=1&user_ids[1]=2 and user_ids[]=1&user_ids[]=2, but not support user_ids=1&user_ids=2 or user_ids=1,2. (Also mentioned in PR #83 )

It's very important when developing public API (for example, any API shared by openAPI). If an API only determined that a query parameter is an array, then there will be various client implementation with various array forms.