Small style changes

osu.Game.Tests/Visual/TestCaseChatLink.cs

@@ -66,8 +66,8 @@ private void load()
 
         private class DummyMessage : Message
         {
-            private static long messageCounter = 0;
-            private static User sender = new User
+            private static long messageCounter;
+            private readonly static User sender = new User
             {
                 Username = @"Somebody",
                 Id = 1,

osu.Game/Overlays/Chat/ChatLine.cs

@@ -256,7 +256,6 @@ private void updateMessageContent()
                     });
                 }
 
-                // Add text after the last link
                 var lastLink = message.Links[message.Links.Count - 1];
                 contentFlow.AddText(message.Content.Substring(lastLink.Index + lastLink.Length));
             }