Remove the 'C-k' binding in ido-mode

* lisp/ido.el (ido-file-completion-map): Remove the `C-k' binding,
because it's too dangerous and probably not very useful (bug#44556).

etc/NEWS

@@ -103,6 +103,14 @@ of 'user-emacs-directory'.
 
 * Incompatible changes in Emacs 29.1
 
+---
+** 'C-k' no longer deletes files in 'ido-mode'.
+To get the previous action back, put something like the following in
+your init file:
+
+  (require 'ido)
+  (keymap-set ido-file-completion-map "C-k" #'ido-delete-file-at-head)
+
 ---
 ** New user option 'term-clear-full-screen-programs'.
 By default, term will now work like most terminals when displaying

lisp/ido.el

@@ -978,7 +978,6 @@ The fallback command is passed as an argument to the functions."
 (defvar-keymap ido-file-completion-map
   :doc "Keymap for Ido file commands."
   :parent ido-file-dir-completion-map
-  "C-k" #'ido-delete-file-at-head
   "C-o" #'ido-copy-current-word
   "C-w" #'ido-copy-current-file-name
   "M-l" #'ido-toggle-literal)