Return the query as a container of parameters.
This function returns a bidirectional view of key/value pairs over the query. The returned view references the same underlying character buffer; ownership is not transferred. Any percent-escapes in strings returned when iterating the view are decoded first. The container is modifiable; changes to the container are reflected in the underlying URL.
params_ref pv = url( "/sql?id=42&name=jane%2Ddoe&page+size=20" ).params();
query = *( pchar / "/" / "?" ) query-param = key [ "=" value ] query-params = [ query-param ] *( "&" query-param )