Make indented-text-mode alias obsolete

* lisp/textmodes/text-mode.el (indented-text-mode): Make compat
alias obsolete.
* lisp/allout.el (allout-use-hanging-indents):
* lisp/emulation/viper.el (viper-vi-state-mode-list):
* lisp/textmodes/remember.el (remember-mode):
* lisp/textmodes/text-mode.el (text-mode-map):
* lisp/vc/ediff-util.el (ediff-choose-syntax-table): Don't mention or
use above obsolete alias.

lisp/textmodes/remember.el

@@ -556,7 +556,7 @@ If this is nil, then `diary-file' will be used instead."
     map)
   "Keymap used in `remember-mode'.")
 
-(define-derived-mode remember-mode indented-text-mode "Remember"
+(define-derived-mode remember-mode text-mode "Remember"
   "Major mode for output from \\[remember].
 This buffer is used to collect data that you want to remember.
 \\<remember-mode-map>

lisp/textmodes/text-mode.el

@@ -72,8 +72,8 @@
     (define-key map "\e\t" #'ispell-complete-word)
     map)
   "Keymap for `text-mode'.
-Many other modes, such as `mail-mode', `outline-mode' and `indented-text-mode',
-inherit all the commands defined in this map.")
+Many other modes, such as `mail-mode' and `outline-mode', inherit
+all the commands defined in this map.")
 
 (easy-menu-define text-mode-menu text-mode-map
   "Menu for `text-mode'."
@@ -164,8 +164,6 @@ Turning on Paragraph-Indent minor mode runs the normal hook
     (remove-function (local 'indent-line-function)
                      #'indent-to-left-margin)))
 
-(defalias 'indented-text-mode #'text-mode)
-
 ;; This can be made a no-op once all modes that use text-mode-hook
 ;; are "derived" from text-mode.  (As of 2015/04, and probably well before,
 ;; the only one I can find that doesn't so derive is rmail-edit-mode.)
@@ -245,6 +243,8 @@ The argument NLINES says how many lines to center."
 	   (setq nlines (1+ nlines))
 	   (forward-line -1)))))
 
+(define-obsolete-function-alias 'indented-text-mode #'text-mode "29.1")
+
 (provide 'text-mode)
 
 ;;; text-mode.el ends here