[crosscode] add an icon for the Arch mod

crosscode/btw-i-use-arch-mod/README.md

@@ -0,0 +1 @@
+The file [`icon24.png`](icon24.png) was cropped from the file [`/usr/share/archlinux/web/arch83x31.gif`](file:///usr/share/archlinux/web/arch83x31.gif) of the AUR package [`archlinux-artwork`](https://aur.archlinux.org/packages/archlinux-artwork/) and is distributed under the CC-BY-NC-SA license.

crosscode/btw-i-use-arch-mod/ccmod.json

@@ -2,6 +2,9 @@
   "id": "btw-i-use-arch",
   "title": "btw I use Arch",
   "description": "A mod for masochists like myself",
+  "icons": {
+    "24": "icon24.png"
+  },
   "prestart": "prestart.js",
   "poststart": "poststart.js"
 }