Use ፧ (Ethiopian question mark) for missing battery

dotfiles/i3status.conf

@@ -20,7 +20,7 @@ order += "tztime local"
 
 battery 0 {
        format = "%status %percentage %remaining"
-       format_down = "?B0"
+       format_down = "፧B0"
        status_chr = "⚇C0"
        status_bat = "⚡B0"
        status_full = "☻F0"