bug#32210: Support medium weighted fonts

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: carlosjosepita@gmail.com,  32210@debbugs.gnu.org
> Date: Wed, 20 Oct 2021 16:42:17 +0200
> 
> > If I change
> >
> >   { 210, { "black", "heavy" }},
> 
> fc-query /usr/share/fonts/opentype/noto/NotoSansCJK-Black.ttc
> 
> has
> 
>         weight: 210(f)(s)
> 
> So these are actually the weights in the font files?  Which is a
> separate system from the Pango weights...

Yes, and see, e.g., ftfont.c, where we query fontconfig for these
values.