bug#65049: Minor update to the repro steps

[Juri Linkov]

> Yes, but where did the file git-patchyYAcN5 come from in the first
> place?  It's that file that is the problem, not how we apply the
> diffs in that file.

It's created in 'vc-git-checkin':

        (let ((patch-file (make-nearby-temp-file "git-patch")))
          (with-temp-file patch-file
            (insert vc-git-patch-string))
          (unwind-protect
              (vc-git-command nil 0 patch-file "apply" "--cached")