Seal/abstract/virtual everything (#6739)

Content.Client/Chemistry/UI/ChemMasterWindow.xaml.cs

@@ -26,7 +26,7 @@ namespace Content.Client.Chemistry.UI
     /// Client-side UI used to control a <see cref="SharedChemMasterComponent"/>
     /// </summary>
     [GenerateTypedNameReferences]
-    public partial class ChemMasterWindow : DefaultWindow
+    public sealed partial class ChemMasterWindow : DefaultWindow
     {
         [Dependency] private readonly IPrototypeManager _prototypeManager = default!;
         public event Action<string>? OnLabelEntered;
@@ -267,7 +267,7 @@ namespace Content.Client.Chemistry.UI
         }
     }
 
-    public class ChemButton : Button
+    public sealed class ChemButton : Button
     {
         public FixedPoint2 Amount { get; set; }
         public bool IsBuffer = true;