bug#23033: 24.5; Lock file uses the same extension as the file it's locking

[Eli Zaretskii]

> From: Michael Sloan <mgsloan@gmail.com>
> Date: Fri, 8 Nov 2019 22:17:29 -0800
> Cc: Eli Zaretskii <eliz@gnu.org>, Glenn Morris <rgm@gnu.org>, 
> 23033@debbugs.gnu.org
> 
> Appending `.lock` seems fine to me (note the period rather than hyphen).  I 
> don't find it ugly, instead
> explanatory!  If users do see these file names, then it is clearer that they 
> are lock files.  There is precedent for
> use of this file extension[0], and there's also lots of precedent for 
> stacking file extensions.
> 
> I propose keeping the traditional `.#` prefix but adding a `.lock` suffix.

I think we should only consider adding punctuation characters, because
that would ensure these lock files are displayed right next to the
files they lock, like today.  Moving the lock files away of the files
they lock in the directory listing would be a disadvantage, IMO.