Update events.cs

Gladly taking suggestions for a better comments.

docs/guides/concepts/samples/events.cs

@@ -8,7 +8,11 @@ public class Program
 	
 	public async Task MainAsync()
 	{
-		_client = new DiscordSocketClient();
+		// When working with events that have Cacheable<IMessage, ulong> parameters,
+		// you must enable the message cache in your config settings if you plan to
+		// use the cached message entity. 
+		_config = new DiscordSocketConfig { MessageCacheSize = 100 };
+		_client = new DiscordSocketClient(_config);
 
 		await _client.LoginAsync(TokenType.Bot, "bot token");
 		await _client.StartAsync();
@@ -25,7 +29,8 @@ public class Program
 
 	private async Task MessageUpdated(Cacheable<IMessage, ulong> before, SocketMessage after, ISocketMessageChannel channel)
 	{
+		// If the message was not in the cache, downloading it will result in getting a copy of `after`.
 		var message = await before.GetOrDownloadAsync();
 		Console.WriteLine($"{message} -> {after}");
 	}
-}
+}