With this patch, we can move directories into new directories if we
explicitly end the new name with a trailing slash.

So `/new_name` renames `/old_name` to `/new_name`, while `/new_name/`
renames `/old_name` to `/new_name/old_name`.

Without this feature, one has to first create the new directory and then
move the old directory into it, which is so unpleasant I currently just
copy the path and use my shell's move functions.

PS: Please use reply-to-all, I am currently not subscribed to the list.