Santize @ for discord (#22)

* Santize @ for discord

* Replace @ with (at)

* Oopsie poopsies

Author: pbjames

src/main/java/com/cssbham/minecraftcore/util/MessageUtil.java

@@ -22,6 +22,6 @@ public static String getChatColor(String color) {
     }
 
     public static String sanitise(String message) {
-        return ChatColor.stripColor(MarkdownSanitizer.sanitize(message));
+        return ChatColor.stripColor(MarkdownSanitizer.sanitize(message).replace("@", "(at)"));
     }
 }