Initial value

So far using your library has been an excellent help with my CLI project - The autocomplete functionality makes for a very useful all-round input. I'm wondering what the scope might be to add more features to this, as I'd prefer to just use `autocomplete-cli` instead of adding other libraries.

Would you consider adding an `initialValue` or `value` property to allow someone to _pre-fill_ the input before they can type? This would allow for someone to say "edit" a value rather than have to enter something. If they wanted to change one character, for example, this would be the best way.

Start by locating the CLI's autocomplete input handling and how its current value is initialized. Confirm the option name and cursor behavior, then verify that a supplied value appears before typing and can be edited, including changing a single character.

Written by the indexing model from the issue text.