Returns the replacement in replace-list that would be used for the target that matches in string at pos See also repl-substring-list?.
(define (repl-substring-list-repl string replace-list pos)
;; Return the replacement that would be used in the string
(let loop ((list replace-list))
(let ((target (car list))
(repl (car (cdr list)))
(rest (cdr (cdr list))))
(if (repl-substring? string target pos)
repl
(if (null? rest)
#f
(loop rest))))))