bug#49193: Document require-final-newline vs. readonly files

[Eli Zaretskii]

> From: Michael Heerdegen <michael_heerdegen@web.de>
> Cc: eliz@gnu.org,  jidanni@jidanni.org
> Date: Fri, 25 Jun 2021 00:08:34 +0200
> 
> | If the value is ‘visit’, Emacs adds a newline at the end of any file
> | that doesn’t have one, just after it visits the file...
> 
> But that's not true, is it?  The file is not touched.  Is the newline
> still added to the file's buffer?  Or not even that (because the buffer
> is read-only)?
> 
> Would
> 
> | [...] Emacs adds a newline at the end of any file's buffer that
> | doesn’t have one, just after it visits the file...
> 
> be clearer?

Depends on the beholder, I guess.  Many newbies don't understand the
fine difference, and have trouble with the idea that Emacs doesn't
generally manipulate files for editing.