fix: Address review

src/Avalonia.Controls.DataGrid/DataGrid.cs

@@ -48,7 +48,6 @@ namespace Avalonia.Controls
         private const string DATAGRID_elementColumnHeadersPresenterName = "PART_ColumnHeadersPresenter";
         private const string DATAGRID_elementFrozenColumnScrollBarSpacerName = "PART_FrozenColumnScrollBarSpacer";
         private const string DATAGRID_elementHorizontalScrollbarName = "PART_HorizontalScrollbar";
-        private const string DATAGRID_elementRowHeadersPresenterName = "PART_RowHeadersPresenter";
         private const string DATAGRID_elementTopLeftCornerHeaderName = "PART_TopLeftCornerHeader";
         private const string DATAGRID_elementTopRightCornerHeaderName = "PART_TopRightCornerHeader";
         private const string DATAGRID_elementBottomRightCornerHeaderName = "PART_BottomRightCorner";

src/Avalonia.Controls.DataGrid/DataGridColumnHeader.cs

@@ -34,7 +34,6 @@ namespace Avalonia.Controls
         }
 
         private const int DATAGRIDCOLUMNHEADER_resizeRegionWidth = 5;
-        private const double DATAGRIDCOLUMNHEADER_separatorThickness = 1;
         private const int DATAGRIDCOLUMNHEADER_columnsDragTreshold = 5;
 
         private bool _areHandlersSuspended;

src/Avalonia.Controls.DataGrid/DataGridRowHeader.cs

@@ -18,8 +18,6 @@ namespace Avalonia.Controls.Primitives
     public class DataGridRowHeader : ContentControl
     {
         private const string DATAGRIDROWHEADER_elementRootName = "PART_Root";
-        private const double DATAGRIDROWHEADER_separatorThickness = 1;
-
         private Control _rootElement;
 
         public static readonly StyledProperty<IBrush> SeparatorBrushProperty =

src/Avalonia.Native/ClipboardImpl.cs

@@ -15,8 +15,7 @@ namespace Avalonia.Native
         private IAvnClipboard _native;
         private const string NSPasteboardTypeString = "public.utf8-plain-text";
         private const string NSFilenamesPboardType = "NSFilenamesPboardType";
-        private const string NSPasteboardTypeFileUrl = "public.file-url";
-        
+
         public ClipboardImpl(IAvnClipboard native)
         {
             _native = native;

src/Browser/Avalonia.Browser/BrowserNativeControlHost.cs

@@ -55,12 +55,6 @@ namespace Avalonia.Browser
 
         private class Attachment : INativeControlHostControlTopLevelAttachment
         {
-            private const string InitializeWithChildHandleSymbol = "InitializeWithChildHandle";
-            private const string AttachToSymbol = "AttachTo";
-            private const string ShowInBoundsSymbol = "ShowInBounds";
-            private const string HideWithSizeSymbol = "HideWithSize";
-            private const string ReleaseChildSymbol = "ReleaseChild";
-
             private JSObject? _native;
             private BrowserNativeControlHost? _attachedTo;
 

src/Windows/Avalonia.Win32/WindowImpl.cs

@@ -1343,8 +1343,6 @@ namespace Avalonia.Win32
         }
 
         private const int MF_BYCOMMAND = 0x0;
-        private const int MF_BYPOSITION = 0x400;
-        private const int MF_REMOVE = 0x1000;
         private const int MF_ENABLED = 0x0;
         private const int MF_GRAYED = 0x1;
         private const int MF_DISABLED = 0x2;