Seal/abstract/virtual everything (#6739)

Content.Server/Doors/Systems/DoorSystem.cs

@@ -153,7 +153,7 @@ public sealed class DoorSystem : SharedDoorSystem
         if (canEv.Cancelled)
             // mark handled, as airlock component will cancel after generating a pop-up & you don't want to pry a tile
             // under a windoor.
-            return true; 
+            return true;
 
         var modEv = new DoorGetPryTimeModifierEvent();
         RaiseLocalEvent(target, modEv, false);
@@ -305,7 +305,7 @@ public sealed class DoorSystem : SharedDoorSystem
     }
 }
 
-public class PryFinishedEvent : EntityEventArgs { }
-public class PryCancelledEvent : EntityEventArgs { }
-public class WeldFinishedEvent : EntityEventArgs { }
-public class WeldCancelledEvent : EntityEventArgs { }
+public sealed class PryFinishedEvent : EntityEventArgs { }
+public sealed class PryCancelledEvent : EntityEventArgs { }
+public sealed class WeldFinishedEvent : EntityEventArgs { }
+public sealed class WeldCancelledEvent : EntityEventArgs { }