" " is always inserted after a completion

I think it is this code here https://github.com/judah/haskeline/blob/28ee26ad5b4ae1c0584f2ec11ac53be9671bf878/System/Console/Haskeline/Command/Completion.hs#L22

As far as I can tell there is no way to configure this.

Most of the time that behavour is what is wanted,
but sometimes it isn't, so it would be good to present a way to write a `Completion` that doesns't do that.

Example of when it is not wanted is if I have a keyword that must always be followed by a quoted string, then I would like to complete up to and include the openning quote. eg `ope` → `open "`
but right now that would effectively complete to `open " ` (not the a space after the `"`)