Revert "Handle buffer pos in ivy--action-insert"

This reverts commit 9f0e989.

ivy.el

@@ -4578,12 +4578,10 @@ Otherwise, forward to `ivy-kill-line'."
     x))
 
 (defun ivy--action-insert (x)
-  (insert (cond ((stringp x) (ivy--trim-grep-line-number x))
-                ;; swiper-isearch passes buffer pos
-                ((numberp x) (save-excursion
-                               (goto-char x)
-                               (buffer-substring (line-beginning-position) (line-end-position))))
-                (t x (car x)))))
+  (insert
+   (if (stringp x)
+       (ivy--trim-grep-line-number x)
+       x (car x))))
 
 (defun ivy--action-copy (x)
   (kill-new