restore max_item_count

lua/cmp/types/cmp.lua

@@ -162,6 +162,7 @@ cmp.ItemField = {
 ---@field public trigger_characters string[]|nil
 ---@field public keyword_pattern string|nil
 ---@field public keyword_length integer|nil
+---@field public max_item_count integer|nil
 ---@field public group_index integer|nil
 ---@field public entry_filter nil|function(entry: cmp.Entry, ctx: cmp.Context): boolean