programs.rofi.font is not set correctly

[qaristote]

I'm using Stylix and enabled Rofi inside Home Manager but it doesn't pick up the right font. Looking at the source, this seems to be because Stylix sets

stylix/modules/rofi/hm.nix

Lines 20 to 21 in 6d3a046

	programs.rofi = {
	font = monospace.name;

Whereas this option actually expects the name of the font followed by the font size.
A possible fix would thus be to set

programs.font.rofi = "${monospace.name} 12"

but the font size should probably depend on some option.

[dwarfmaster]

Related issue #35
As I said there, we need a way to handle font sizes. I haven't really had the time to think about it yet.