Make the regexp less restrictive and don't require the outline heading
to have more text after outline-regexp until the end of the heading line
(bug#51016).
(defvar outline-font-lock-keywords
'(
;; Highlight headings according to the level.
- (eval . (list (concat "^\\(?:" outline-regexp "\\).+")
+ (eval . (list (concat "^\\(?:" outline-regexp "\\).*")
0 '(if outline-minor-mode
(if outline-minor-mode-cycle
(if outline-minor-mode-highlight