bug#39359: [patch] TUTORIAL: Be accurate about "buffer" vs "file"; capitalize Dired. Four other trivial TUTORIAL patches

[Eli Zaretskii]

> From: Jorge P. de Morais Neto <jorge+list@disroot.org>
> Cc: Eli Zaretskii <eliz@gnu.org>, 39359@debbugs.gnu.org
> Date: Sun, 07 Jun 2020 13:20:46 -0300
> 
> - For consistency with C-x C-f ("Find file") and C-x C-s ("Save file"),
>   refer to C-x s as "Save some files".

But that is inaccurate: "C-x C-f" indeed reads a file into a buffer,
but "C-x C-f" saves the _buffer_ into its file.  "Save file" is not
what "C-x C-s" does, since the file is not saved anywhere.

How about saying "Save some buffers to their files" instead?

Thanks.