bug#25216: 26.0.50 [regression]; Curly quotes are not found in some sizes of ‘Terminus’ font

[Dmitry Alexandrov]

> "M-x describe-fontset" is what you want.

By studying what it says, I accidentally found a workaround, that does not 
imply nor careful enumeration of characters that ‘Terminus’ support in order to 
add them to ‘fontset-default’ nor clogging ‘fontset-default’ with erroneous 
rules.

   $ emacs --quick --font '-*-terminus-medium-r-*-*-20-*-*-*-*-*-*-*'

   (set-fontset-font "-*-Terminus-*-fontset-startup"
                     '(0 . #x3FFFFF)
                     "Terminus")

Looks very much like (setq a a), but works like a charm!