> Maybe then better to add an intermediate mapping to hi-lock
> like there is in isearch: isearch-message vs isearch-string,
> where isearch-message is user-facing representaion,
> and isearch-string contains internal data.

This patch adds a new variable hi-lock-interactive-lighters
(where the word 'lighter' refers to minor mode's lighters)
that holds a mapping from either isearch-string or manually
entered regexp to a closure used in font-lock-keywords: