Variable: completion-show-inline-help
completion-show-inline-help is a variable defined in minibuffer.el.gz.
Value
t
Documentation
If non-nil, print helpful inline messages during completion.
Source Code
;; Defined in /usr/src/emacs/lisp/minibuffer.el.gz
(defvar completion-show-inline-help t
"If non-nil, print helpful inline messages during completion.")