fix: rename {b,e}ol functions to pos-{b,e}ol

These two functions were introduced in emacs-mirror/emacs@f117b5df4d
as `bol` and `eol`, but were renamed to `pos-bol` and `pos-eol` in
emacs-mirror/emacs@2614e53216.

Close: #8242

lisp/lib/print.el

@@ -344,7 +344,7 @@ based on the print level of the message. For example:
       (letf! (defun current-fill-column ()
                (let ((target (funcall current-fill-column)))
                  (save-excursion
-                   (goto-char (line-beginning-position))
+                   (goto-char (pos-bol))
                    (let ((n 0)
                          (c 0))
                      (while (and (not (eolp)) (<= n target))