missing `"GET"` argument in `messageGet`

[tinkerer-red]

Here is the replacement to fix this.

	static messageGet = function(_channelId, _messageId, _callback = -1){
		// Prepare the url and headers
		var _urlEndpoint = "channels/" + _channelId + "/messages/" + _messageId;	
		__discord_send_http_request_standard(_urlEndpoint, "GET", -1, __botToken, _callback);
	}

I will likely make a pull request for these changes, reporting them for now incase I forget.