bug#3717: M-x man completion

[Kevin Ryde]

I wrote:
>
> insinuate "-k " and "-l " so it's possible to type those things
> without needing C-q Space.

I've since thought to help any "-" option, not just -k and -l, with a
constructed table in the completion handler along these lines.

Not sure it's fantastic for "?" or "tab", but gets the right effect on
space.


        ((string-match "\\`-\\(.\\)?" str)
         ;; "-" or "-X" -- alone and with a space so you don't have to type
         ;; C-q space after an option.  "-l" or "-k" are shown as standard
         ;; options, but then add anything else so other options can be
         ;; typed.
         ;;
         ;; For formatting options like "-Tascii" could think about applying
         ;; the pagename or filename completion to the next arg, but
         ;; normally such options will go in `Man-switches'.
         ;;
         (let ((table '(("-l " . "run man on a file")
                        ("-k " . "search apropos database"))))
           (unless (member str '("-k" "-l" "-k " "-l "))
             (push (cons str "option") table)
             (push (cons (concat str " ") "option") table))
           (man-completion--complete-with-action action table str pred)))