Remove explicit private.

Remove unnecessary delegate.
Use extension method syntax.
Fix HealthInfo.NotifyAppliedDamage’s desc.
Remove unused using directives.
Remove explicit type declaration in Manifest.

OpenRA.Game/Traits/World/Shroud.cs

@@ -331,7 +331,7 @@ namespace OpenRA.Traits
 
 		public bool IsExplored(Actor a)
 		{
-			return GetVisOrigins(a).Any(o => IsExplored(o));
+			return GetVisOrigins(a).Any(IsExplored);
 		}
 
 		public bool IsVisible(CPos cell)