Move placeholders to a dedicated namespace

osu.Game.Tests/Visual/SongSelect/TestSceneBeatmapLeaderboard.cs

@@ -7,6 +7,7 @@ using osu.Framework.Graphics;
 using osu.Game.Beatmaps;
 using osu.Game.Online.API.Requests.Responses;
 using osu.Game.Online.Leaderboards;
+using osu.Game.Online.Placeholders;
 using osu.Game.Rulesets.Osu.Mods;
 using osu.Game.Scoring;
 using osu.Game.Screens.Select.Leaderboards;

osu.Game/Online/Leaderboards/Leaderboard.cs

@@ -14,6 +14,7 @@ using osu.Framework.Threading;
 using osu.Game.Graphics.Containers;
 using osu.Game.Graphics.UserInterface;
 using osu.Game.Online.API;
+using osu.Game.Online.Placeholders;
 using osuTK;
 using osuTK.Graphics;
 

osu.Game/Online/Leaderboards/RetrievalFailurePlaceholder.cs

@@ -6,6 +6,7 @@ using osu.Framework.Graphics;
 using osu.Framework.Graphics.Sprites;
 using osu.Framework.Input.Events;
 using osu.Game.Graphics.Containers;
+using osu.Game.Online.Placeholders;
 using osuTK;
 
 namespace osu.Game.Online.Leaderboards

osu.Game/Online/Placeholders/MessagePlaceholder.cs

@@ -4,7 +4,7 @@
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Sprites;
 
-namespace osu.Game.Online.Leaderboards
+namespace osu.Game.Online.Placeholders
 {
     public class MessagePlaceholder : Placeholder
     {

osu.Game/Online/Placeholders/Placeholder.cs

@@ -5,7 +5,7 @@ using System;
 using osu.Framework.Graphics;
 using osu.Game.Graphics.Containers;
 
-namespace osu.Game.Online.Leaderboards
+namespace osu.Game.Online.Placeholders
 {
     public abstract class Placeholder : OsuTextFlowContainer, IEquatable<Placeholder>
     {