I am providing you info but I told I made experimetns with fonts that rendered font nor encoding as cause.
`geany 1.34.1 (built on 2019-06-01 with GTK 3.24.20, GLib 2.62.6)`
I tried in Geany for instance: ⭑ DejavVu Sans Mono Book 9 + UTF-8 ⭑ DejavVu Sans Mono Book 9 + WINDOWS-1252 ⭑ DejavVu Sans Mono Book 13 + WINDOWS-1252 ⭑ Courier Regular 16 + UTF-8 ⭑ Courier Regular 9 + UTF-8
All the same.