https://github.com/neoclide/coc.nvim#example-vim-configuration
[[lazy.nvim]]の設定。
```lua
keys = {
{ "<down>", [[coc#pum#visible() ? coc#pum#next(1) : "<down>"]], mode = "i", expr = true, replace_keycodes = false },
{ "<up>", [[coc#pum#visible() ? coc#pum#prev(1): "<up>"]], mode = "i", expr = true, replace_keycodes = false }
}
```