completion--replace: Fix completion cycling

completion--replace: Fix completion cycling

* lisp/minibuffer.el (completion--replace):
Don't "insert before markers" after all because in some cases
(https://lists.gnu.org/archive/html/emacs-devel/2024-05/msg00701.html)
- like cycling - BEG can be denoted by a marker as well.
(minibuffer-completion-help): Make FIELD-END simply a fixnum.  And
adjust its value manually inside the local
completion-list-insert-choice-function (bug#48356).

(cherry picked from commit 2c759b9ce620311df97f43b791ba27b1302171c4)