feat: allow custom prompt infolist

lua/artio/config.lua

···
 ---@field prompt_title boolean
 ---@field pointer string
 ---@field marker string
+---@field infolist ('index'|'list')[]
 ---@field use_icons boolean
 
 ---@class artio.config.win
···
     prompt_title = true,
     pointer = "",
     marker = "│",
+    infolist = { "list" }, -- index: [1] list: (4/5)
     use_icons = _G["MiniIcons"] and true or false,
   },
   win = {

lua/artio/view.lua

···
   return result
 end
 
+---@param p artio.Picker
+---@param info 'index'|'list'|string
+---@return string
+local function getpromptinfo(p, info)
+  if info == "index" then
+    return ("[%d]"):format(p.idx)
+  elseif info == "list" then
+    return ("(%d/%d)"):format(#p.matches, #p.items)
+  end
+  return ""
+end
+
 function View:drawprompt()
   logdebug("drawprompt")
 
···
     self:mark("promptinfo", promptidx, 0, {
       virt_text = {
         {
-          ("[%d] (%d/%d)"):format(self.picker.idx, #self.picker.matches, #self.picker.items),
+          table.concat(
+            vim
+              .iter(self.picker.opts.infolist)
+              :map(function(info)
+                return getpromptinfo(self.picker, info)
+              end)
+              :totable(),
+            " "
+          ),
           "InfoText",
         },
       },