bug#39360: Add :extend attribute to show-paren-mode expression face

[Eli Zaretskii]

> Cc: 39360@debbugs.gnu.org
> From: martin rudalics <rudalics@gmx.at>
> Date: Fri, 31 Jan 2020 16:44:27 +0100
> 
>  > Is there a reason to highlight one blank space at the end of each line, 
> though, instead of only highlighting the text?
> 
> It continues to irritate me as well.  Maybe an option to turn it off?

IMO, it's too early to discuss such an option: we don't yet know how
this feature will end up in Emacs 27 and beyond, because we didn't yet
have enough user feedback.  What we have now is similar to how other
programs behave, including highlighting of the space beyond EOL.  Does
it irritate you in those other programs as well?