bug#48456: Revert Dired after copy/rename

[Juri Linkov <juri@linkov.net>]

>   Test dired-test-bug30624 condition:
>       (ert-test-failed
>        ((should
>          (dired-do-create-files 'copy 'dired-copy-file "Copy" nil))
>         :form
>         (dired-do-create-files copy dired-copy-file "Copy" nil)
>         :value nil))
>
> Should the 'should' be removed?  AFAICT the return value of
> dired-do-create-files is unspecified (and unused).

It's hard to guess how important the return value was.
It seems the return value of dired-do-create-files
via dired-create-files and via dired-move-to-filename
was the position of the beginning of the filename,
or nil if none found.

If it should be preserved, then dired-do-create-files
could be changed to something like this:

      (prog1 (dired-create-files
        ...
        (when (or (eq dired-do-revert-buffer t)
        ...

Otherwise, the 'should' should be replaced with

diff --git a/test/lisp/dired-aux-tests.el b/test/lisp/dired-aux-tests.el
index 7f1743f88d..1fd14e72aa 100644
--- a/test/lisp/dired-aux-tests.el
+++ b/test/lisp/dired-aux-tests.el
@@ -109,7 +109,8 @@ dired-test-bug30624
           (progn
             (dired-revert)
             (dired-mark-files-regexp "bug30624_file")
-            (should (dired-do-create-files 'copy 'dired-copy-file "Copy" nil)))
+            (dired-do-create-files 'copy 'dired-copy-file "Copy" nil)
+            (should (dired-move-to-filename)))
         (delete-directory target-dir 'recursive)
         (mapc #'delete-file `(,file1 ,file2))
         (kill-buffer buf)))))