Update 'gmcommand.lua'

Adjusted to include DSP's new ! command usage.

gmcommand.lua

@@ -35,7 +35,7 @@ require 'common'
 ----------------------------------------------------------------------------------------------------
 ashita.register_event('command', function(command, ntype)
     -- Look for commands starting with @
-    if (command:startswith('@')) then
+    if (command:startswith('@') or command:startswith('!')) then
         AshitaCore:GetChatManager():QueueCommand('$' .. command:remove(1), 1);
         return true;
     end