From NeoVim's `completeopt` documentation:
> noselect Do not select a match in the menu, force the user to
> select one from the menu. Only works in combination with
> "menu" or "menuone".
When `completeopt = "menu,menuone,noselect"` is used, custom completion
menu does not respect `noselect` and preselects the first item. No
preselection happens in case of native menu.
This patch addresses the bug and ensures that in case of custom menu no
items are preselected if `noselect` is specified in `completeopt`.
Fixes#332
1e7355a5fb