Doc fixes: don't refer to some obsolete items

* admin/notes/multi-tty:
* lisp/chistory.el (command-history):
* lisp/emacs-lisp/nadvice.el:
* lisp/vc/diff-mode.el: Doc fix; don't refer to obsolete variables and
functions.

admin/notes/multi-tty

@@ -474,7 +474,7 @@ THINGS TO DO
    definition.
 
    Exceptions found so far: x-select-text and
-   x-selection-value (old name: x-cut-buffer-or-selection-value).
+   x-selection-value.
 
 ** Have a look at fatal_error_hook.
 

lisp/chistory.el

@@ -165,11 +165,11 @@ The buffer for that command is the previous current buffer."
   "Examine commands from variable `command-history' in a buffer.
 The number of commands listed is controlled by `list-command-history-max'.
 The command history is filtered by `list-command-history-filter' if non-nil.
-Use \\<command-history-map>\\[command-history-repeat] to repeat the command on the current line.
+Use \\<command-history-mode-map>\\[command-history-repeat] to repeat the command on the current line.
 
 Otherwise much like Emacs-Lisp Mode except that there is no self-insertion
 and digits provide prefix arguments.  Tab does not indent.
-\\{command-history-map}
+\\{command-history-mode-map}
 
 This command always recompiles the Command History listing
 and runs the normal hook `command-history-hook'."

lisp/emacs-lisp/nadvice.el

@@ -277,7 +277,7 @@ different, but `function-equal' will hopefully ignore those differences.")
 (defmacro add-function (where place function &optional props)
   ;; TODO:
   ;; - maybe let `where' specify some kind of predicate and use it
-  ;;   to implement things like mode-local or eieio-defmethod.
+  ;;   to implement things like mode-local or cl-defmethod.
   ;;   Of course, that only makes sense if the predicates of all advices can
   ;;   be combined and made more efficient.
   ;; :before is like a normal add-hook on a normal hook.

lisp/vc/diff-mode.el

@@ -2053,7 +2053,7 @@ For use in `add-log-current-defun-function'."
       (re-search-forward "^[^ ]" nil t))
     (pcase-let ((`(,buf ,_line-offset ,pos ,src ,dst ,switched)
                  (ignore-errors         ;Signals errors in place of prompting.
-                   ;; Use `noprompt' since this is used in which-func-mode
+                   ;; Use `noprompt' since this is used in which-function-mode
                    ;; and such.
                    (diff-find-source-location nil nil 'noprompt))))
       (when buf