Completion tweaks

[garlic0x1]

Allow the order of completions to be reversed, this is helpful when the prompt is at the bottom of the screen so you don't have to move your eyes.

I am using this in my config so that completions are reversed in regular prompts, but normal in code completion:

(add-hook *prompt-after-activate-hook*
          (lambda ()
            (setf lem/completion-mode::*completion-reverse* t)
            (call-command 'lem/prompt-window::prompt-completion nil)))

(add-hook *prompt-deactivate-hook*
          (lambda ()
            (setf lem/completion-mode::*completion-reverse* nil)
            (lem/completion-mode:completion-end)))