Use system default monospace font

[bertob]

Apparently the default monospace font is stored in gsettings, and not automatically used in Sourceviews for some reason, that's why we're getting the ugly fallback :(

I asked on Matrix, and people said we should have a look at the gsetting org.gnome.desktop.interface monospace-font-name. If that doesn't work, use whatever portal API is available (ashpd? libportal?) to get that same value from settings portal.

[jsparber]

Yes pretty easy to do, it's kinda odd that gtk/sourceview doesn't do this automatically.

[bertob]

Alice said she added some new stuff in libadwaita for this, not sure if we'll get it for free with 48 or need to apply a style class or something though.