Move dired-info and dired-man from dired-x to dired

* lisp/dired-x.el (dired-bind-man, dired-bind-info): Change into
defvars and make obsolete.
(dired-extra-startup): Doc fix.
(dired-info, dired-man): Move from here...
* lisp/dired.el (dired-do-info, dired-do-man): ...to here and
rename.  (Bug#21981)

* lisp/dired.el (dired-mode-map): Bind 'I' and 'N' to 'dired-do-info'
and 'dired-do-man'.

* doc/misc/dired-x.texi (Miscellaneous Commands): Remove documentation
of 'dired-info' and 'dired-man'.
* doc/emacs/dired.texi (Dired Enter): Document 'dired-do-info' and
'dired-do-man'.
* etc/NEWS: Announce the above changes.

lisp/dired.el

@@ -2079,8 +2079,10 @@ Do so according to the former subdir alist OLD-SUBDIR-ALIST."
   "D"       #'dired-do-delete
   "G"       #'dired-do-chgrp
   "H"       #'dired-do-hardlink
+  "I"       #'dired-do-info
   "L"       #'dired-do-load
   "M"       #'dired-do-chmod
+  "N"       #'dired-do-man
   "O"       #'dired-do-chown
   "P"       #'dired-do-print
   "Q"       #'dired-do-find-regexp-and-replace
@@ -4795,6 +4797,31 @@ Interactively with prefix argument, read FILE-NAME."
 	      (read-file-name "Jump to Dired file: "))))
   (dired-jump t file-name))
 
+
+;;; Miscellaneous commands
+
+(declare-function Man-getpage-in-background "man" (topic))
+(declare-function dired-guess-shell-command "dired-x" (prompt files))
+(defvar manual-program) ; from man.el
+
+(defun dired-do-man ()
+  "Run `man' on this file."
+  (interactive)
+  (require 'man)
+  ;; FIXME: Move `dired-guess-shell-command' to dired.el to remove the
+  ;;        need for requiring `dired-x'.
+  (require 'dired-x)
+  (let* ((file (dired-get-filename))
+         (manual-program (string-replace "*" "%s"
+                                         (dired-guess-shell-command
+                                          "Man command: " (list file)))))
+    (Man-getpage-in-background file)))
+
+(defun dired-do-info ()
+  "Run `info' on this file."
+  (interactive)
+  (info (dired-get-filename)))
+
 (provide 'dired)
 
 (run-hooks 'dired-load-hook)		; for your customizations