Improve marker visualization for mapping.

Command renamed to showmarkers.
Actually permanent (so if you place markers with it active, you immediately see them).

Content.Client/Commands/DebugCommands.cs

@@ -13,28 +13,14 @@ namespace Content.Client.Commands
     internal sealed class ShowMarkersCommand : IConsoleCommand
     {
         // ReSharper disable once StringLiteralTypo
-        public string Command => "togglemarkers";
+        public string Command => "showmarkers";
         public string Description => "Toggles visibility of markers such as spawn points.";
         public string Help => "";
 
         public bool Execute(IDebugConsole console, params string[] args)
         {
-            bool? whichToSet = null;
-            foreach (var entity in IoCManager.Resolve<IEntityManager>()
-                .GetEntities(new TypeEntityQuery(typeof(SharedSpawnPointComponent))))
-            {
-                if (!entity.TryGetComponent(out ISpriteComponent sprite))
-                {
-                    continue;
-                }
-
-                if (!whichToSet.HasValue)
-                {
-                    whichToSet = !sprite.Visible;
-                }
-
-                sprite.Visible = whichToSet.Value;
-            }
+            EntitySystem.Get<MarkerSystem>()
+                .MarkersVisible ^= true;
 
             return false;
         }