Avoid hard-coding "M-x command" in docstrings

Avoid hard-coding "M-x command" in docstrings

* lisp/calendar/todo-mode.el (todo-mode):
* lisp/desktop.el (desktop-save-mode):
* lisp/edmacro.el (edit-kbd-macro):
* lisp/emacs-lisp/package.el (package-menu-execute):
* lisp/emulation/viper-cmd.el (viper-ask-level):
* lisp/emulation/viper-init.el (viper-expert-level):
* lisp/filesets.el (filesets-add-buffer):
* lisp/follow.el (follow-mode):
* lisp/gnus/auth-source.el (auth-sources):
* lisp/international/ogonek.el (ogonek-informacja)
(ogonek-information):
* lisp/net/tramp.el (tramp-process-actions):
* lisp/org/org-gnus.el (org-gnus-no-new-news):
* lisp/org/org.el (org-ellipsis):
* lisp/progmodes/python.el (python-shell-get-process-or-error):
* lisp/progmodes/vhdl-mode.el (vhdl-mode):
* lisp/server.el (server-start):
* lisp/type-break.el (type-break-noninteractive-query):
* lisp/userlock.el (ask-user-about-supersession-help):
* lisp/whitespace.el (whitespace-report-region):
Prefer (substitute-command-keys "`\\[foo-command]'")
to "`M-x foo-command'" in docstrings and the like.