New key 'M-j' for 'icomplete-mode' (bug#62108)

* lisp/icomplete.el (icomplete-exit): New alias for 'icomplete-fido-exit'.
(icomplete-minibuffer-map): Bind it to "M-j" .

* lisp/replace.el (multi-occur--prompt): Show "M-j" bound to 'icomplete-exit'
in 'icomplete-mode'.

etc/NEWS

@@ -3057,6 +3057,10 @@ Meant to be given a global binding convenient to the user.  Example:
 
 ** Icomplete
 
+*** New key 'M-j' for 'icomplete-mode' and 'icomplete-vertical-mode'.
+Like 'M-j' in 'fido-mode', it can exit the minibuffer with a selected
+candidate even when 'icomplete-show-matches-on-no-input' is non-nil.
+
 *** New user options for 'icomplete-vertical-mode'.
 New user options have been added to enhance 'icomplete-vertical-mode':
 

lisp/icomplete.el

@@ -242,6 +242,7 @@ Used to implement the option `icomplete-show-matches-on-no-input'.")
   :doc "Keymap used by `icomplete-mode' in the minibuffer."
   "C-M-i" #'icomplete-force-complete
   "C-j"   #'icomplete-force-complete-and-exit
+  "M-j"   #'icomplete-exit
   "C-."   #'icomplete-forward-completions
   "C-,"   #'icomplete-backward-completions
   "<remap> <minibuffer-complete-and-exit>" #'icomplete-ret)
@@ -455,6 +456,8 @@ if that doesn't produce a completion match."
       (minibuffer-complete-and-exit)
     (exit-minibuffer)))
 
+(defalias 'icomplete-exit #'icomplete-fido-exit)
+
 (defun icomplete-fido-backward-updir ()
   "Delete char before or go up directory, like `ido-mode'."
   (interactive)

lisp/replace.el

@@ -1878,6 +1878,9 @@ is not modified."
          (bound-and-true-p ido-everywhere))
      (substitute-command-keys
       "(\\<ido-completion-map>\\[ido-select-text] to end): "))
+    ((bound-and-true-p icomplete-mode)
+     (substitute-command-keys
+      "(\\<icomplete-minibuffer-map>\\[icomplete-exit] to end): "))
     ((bound-and-true-p fido-mode)
      (substitute-command-keys
       "(\\<icomplete-fido-mode-map>\\[icomplete-fido-exit] to end): "))