Character replacing other characters missing from the font

Property definitions

gamnit $ BMFontAsset :: _replacement_char
	# Character replacing other characters missing from the font
	private var replacement_char: nullable Char is lazy do
		for c in  "�?".chars do
			if desc.chars.keys.has(c) then return c
		end
		return null
	end
lib/gamnit/bmfont.nit:568,2--574,4