Remove a few warnings.

src/Avalonia.Base/PropertyStore/IPriorityValueEntry.cs

@@ -1,7 +1,4 @@
-using System;
-using Avalonia.Data;
-
-#nullable enable
+#nullable enable
 
 namespace Avalonia.PropertyStore
 {
@@ -10,8 +7,6 @@ namespace Avalonia.PropertyStore
     /// </summary>
     internal interface IPriorityValueEntry : IValue
     {
-        BindingPriority Priority { get; }
-
         void Reparent(IValueSink sink);
     }
 

src/Avalonia.Styling/IStyledElement.cs

@@ -17,11 +17,6 @@ namespace Avalonia
         /// </summary>
         event EventHandler Initialized;
 
-        /// <summary>
-        /// Raised when resources on the element are changed.
-        /// </summary>
-        event EventHandler<ResourcesChangedEventArgs> ResourcesChanged;
-
         /// <summary>
         /// Gets a value that indicates whether the element has finished initialization.
         /// </summary>

src/Avalonia.Styling/StyledElement.cs

@@ -67,7 +67,6 @@ namespace Avalonia
         private List<IStyleInstance>? _appliedStyles;
         private ITemplatedControl? _templatedParent;
         private bool _dataContextUpdating;
-        private bool _notifyingResourcesChanged;
 
         /// <summary>
         /// Initializes static members of the <see cref="StyledElement"/> class.

src/Avalonia.Styling/Styling/Styles.cs

@@ -21,7 +21,6 @@ namespace Avalonia.Styling
         private IResourceHost? _owner;
         private IResourceDictionary? _resources;
         private Dictionary<Type, List<IStyle>?>? _cache;
-        private bool _notifyingResourcesChanged;
 
         public Styles()
         {