Jump to first,last completion with M-<, M-> in icomplete-vertical-mode
Fixes: bug#49005 Co-authored-by: Simon Lang <simon.lang@outlook.com>
* lisp/icomplete.el (icomplete-backward-completions): Return
non-nil iff something was stepped. Ajust docstring.
(icomplete-forward-completions): Adjust docstring.
(icomplete-vertical-goto-first, icomplete-vertical-goto-last): New commands.
(icomplete-vertical-mode-minibuffer-map): Bind new commands to M-< and M->.