The Enable markdown typographer setting converts apostrophes and quotes to the curly ones. We have a bit different characters for these in different European countries 
. It would be super great if this would be supported.
„This would be a correct Czech quote, for example.“
You can find the official summary here.
Oh, I just found this setting: Markdown typographer quotation marks!
So it solves the problem of a single-language forum. But maybe there would be thoughts about this concerning the current multi-lingual forums support?
Thanks @Moin for pointing out that it is possible to influence the defaults based on the default site’s locale. I added Czech version in this PR: