Add li position index to li function in View.Config

[frenchdonuts]

Hello, this feature would be useful to me in the following example:

        customLi keySelected mouseSelected i data =
            { attributes =
                [ attribute "aria-posinset" (toString i)
                , attribute "aria-setsize" (List.length dataList)
                , attribute "role" "option"
                ]
            , children = [ text (dataToString data) ]
            }

which would would allow assistive technologies(AT) like Mac's VoiceOver(VO) to read a list of items along with the index of the current item.

For example, if we have a list of foods:

1. Pizza (upon selection, VO would read "Pizza, 1 of 3")
2. Burger (upon selection, VO would read "Burger, 2 of 3")
3. Chickpeas (upon selection, VO would read "Chickpeas, 3 of 3")

This way, the user of AT always knows where they are in the list.

[frenchdonuts]

So I finally got my fork working, but VO still wasn't reading "{position in list} of {size of set}". It turns out you don't have to set these ARIA attributes if the only li elements present are the filtered ones. Since I no longer need this feature, I'll close this issue.