bug#50928: remove-dups

[Tak Kunihiro]

I wanted to delete duplicated items from a list non-destructively.
It took me a while to find out how to do so.

(cl-remove-duplicates list :test 'equal)
(delete-dups (copy-sequence list))

I think it is handy to have something like below in subr.el.
Too obvious?

#+begin_src emacs-lisp
(defun remove-dups (list)
  "Remove 'equal' duplicates from LIST non-destructively.
Note that `delete-dups' deletes duplicates destructively."
  (delete-dups (copy-sequence list)))
#+end_src