fix(DrawingContext): CS0618 PushPreTransform(Matrix)' is obsolete: 'Use PushTransform'

```bash
Warning CS0618 'DrawingContext.PushPreTransform(Matrix)' is obsolete: 'Use PushTransform' Avalonia.Direct2D1.RenderTests, Avalonia.Skia.RenderTests .\tests\Avalonia.RenderTests\Media\ConicGradientBrushTests.cs 203 Active
Warning CS0618 'DrawingContext.PushPreTransform(Matrix)' is obsolete: 'Use PushTransform' Avalonia.Direct2D1.RenderTests, Avalonia.Skia.RenderTests .\tests\Avalonia.RenderTests\Media\LinearGradientBrushTests.cs 98 Active
Warning CS0618 'DrawingContext.PushPreTransform(Matrix)' is obsolete: 'Use PushTransform' Avalonia.Direct2D1.RenderTests, Avalonia.Skia.RenderTests .\tests\Avalonia.RenderTests\Media\RadialGradientBrushTests.cs 188 Active
Warning CS0618 'DrawingContext.PushPreTransform(Matrix)' is obsolete: 'Use PushTransform' Avalonia.Direct2D1.RenderTests, Avalonia.Skia.RenderTests .\tests\Avalonia.RenderTests\Media\TextFormatting\TextLayoutTests.cs 315 Active
Warning CS0618 'DrawingContext.PushPreTransform(Matrix)' is obsolete: 'Use PushTransform' Avalonia.Skia.UnitTests .\tests\Avalonia.Skia.UnitTests\Media\TextFormatting\TextFormatterTests.cs 795 Active
Warning CS0618 'DrawingContext.PushPreTransform(Matrix)' is obsolete: 'Use PushTransform' ControlCatalog (netstandard2.0) .\samples\ControlCatalog\Pages\CustomDrawingExampleControl.cs 136 Active
Warning CS0618 'DrawingContext.PushPreTransform(Matrix)' is obsolete: 'Use PushTransform' ControlCatalog (netstandard2.0) .\samples\ControlCatalog\Pages\CustomDrawingExampleControl.cs 140 Active
Warning CS0618 'DrawingContext.PushPreTransform(Matrix)' is obsolete: 'Use PushTransform' ControlCatalog (netstandard2.0) .\samples\ControlCatalog\Pages\CustomDrawingExampleControl.cs 144 Active
Warning CS0618 'DrawingContext.PushPreTransform(Matrix)' is obsolete: 'Use PushTransform' ControlCatalog (netstandard2.0) .\samples\ControlCatalog\Pages\CustomDrawingExampleControl.cs 146 Active
Warning CS0618 'DrawingContext.PushPostTransform(Matrix)' is obsolete: 'Use PushTransform' RenderDemo .\samples\RenderDemo\Pages\RenderTargetBitmapPage.cs 32 Active
Warning CS0618 'DrawingContext.PushPreTransform(Matrix)' is obsolete: 'Use PushTransform' Avalonia.Base (net6.0), Avalonia.Base (netstandard2.0) .\src\Avalonia.Base\Media\DrawingGroup.cs 76 Active
Warning CS0618 'DrawingContext.PushPreTransform(Matrix)' is obsolete: 'Use PushTransform' Avalonia.Direct2D1.RenderTests, Avalonia.Skia.RenderTests .\tests\Avalonia.RenderTests\Controls\CustomRenderTests.cs 91 Active
Warning CS0618 'DrawingContext.PushPreTransform(Matrix)' is obsolete: 'Use PushTransform' Avalonia.Direct2D1.RenderTests, Avalonia.Skia.RenderTests .\tests\Avalonia.RenderTests\Controls\CustomRenderTests.cs 115 Active
```

samples/ControlCatalog/Pages/CustomDrawingExampleControl.cs

@@ -133,17 +133,17 @@ namespace ControlCatalog.Pages
 
             // 0,0 refers to the top-left of the control now. It is not prime time to draw gui stuff because it'll be under the world 
 
-            var translateModifier = context.PushPreTransform(Avalonia.Matrix.CreateTranslation(new Avalonia.Vector(halfWidth, halfHeight)));
+            var translateModifier = context.PushTransform(Avalonia.Matrix.CreateTranslation(new Avalonia.Vector(halfWidth, halfHeight)));
 
             // now 0,0 refers to the ViewportCenter(X,Y). 
             var rotationMatrix = Avalonia.Matrix.CreateRotation(Rotation);
-            var rotationModifier = context.PushPreTransform(rotationMatrix);
+            var rotationModifier = context.PushTransform(rotationMatrix);
 
             // everything is rotated but not scaled 
 
-            var scaleModifier = context.PushPreTransform(Avalonia.Matrix.CreateScale(Scale, -Scale));
+            var scaleModifier = context.PushTransform(Avalonia.Matrix.CreateScale(Scale, -Scale));
 
-            var mapPositionModifier = context.PushPreTransform(Matrix.CreateTranslation(new Vector(-ViewportCenterX, -ViewportCenterY)));
+            var mapPositionModifier = context.PushTransform(Matrix.CreateTranslation(new Vector(-ViewportCenterX, -ViewportCenterY)));
 
             // now everything is rotated and scaled, and at the right position, now we're drawing strictly in world coordinates
 

samples/RenderDemo/Pages/RenderTargetBitmapPage.cs

@@ -29,7 +29,7 @@ namespace RenderDemo.Pages
         public override void Render(DrawingContext context)
         {
             using (var ctx = _bitmap.CreateDrawingContext())
-            using (ctx.PushPostTransform(Matrix.CreateTranslation(-100, -100)
+            using (ctx.PushTransform(Matrix.CreateTranslation(-100, -100)
                                          * Matrix.CreateRotation(_st.Elapsed.TotalSeconds)
                                          * Matrix.CreateTranslation(100, 100)))
             {

src/Avalonia.Base/Media/DrawingGroup.cs

@@ -73,7 +73,7 @@ namespace Avalonia.Media
         {
             var bounds = GetBounds();
 
-            using (context.PushPreTransform(Transform?.Value ?? Matrix.Identity))
+            using (context.PushTransform(Transform?.Value ?? Matrix.Identity))
             using (context.PushOpacity(Opacity, bounds))
             using (ClipGeometry != null ? context.PushGeometryClip(ClipGeometry) : default)
             using (OpacityMask != null ? context.PushOpacityMask(OpacityMask, bounds) : default)

src/Avalonia.Base/Rendering/ImmediateRenderer.cs

@@ -83,7 +83,7 @@ namespace Avalonia.Rendering
                     }
                 }
 
-                using (context.PushPostTransform(m))
+                using (context.PushTransform(m))
                 using (context.PushOpacity(opacity, bounds))
                 using (clipToBounds
 #pragma warning disable CS0618 // Type or member is obsolete
@@ -95,7 +95,7 @@ namespace Avalonia.Rendering
 
                 using (visual.Clip != null ? context.PushGeometryClip(visual.Clip) : default)
                 using (visual.OpacityMask != null ? context.PushOpacityMask(visual.OpacityMask, bounds) : default)
-                using (context.PushTransformContainer())
+                using (context.PushTransform(Matrix.Identity))
                 {
                     visual.Render(context);
                     

src/Avalonia.Controls/SelectableTextBlock.cs

@@ -204,7 +204,7 @@ namespace Avalonia.Controls
 
                 var rects = TextLayout.HitTestTextRange(start, length);
 
-                using (context.PushPostTransform(Matrix.CreateTranslation(origin)))
+                using (context.PushTransform(Matrix.CreateTranslation(origin)))
                 {
                     foreach (var rect in rects)
                     {

src/Avalonia.Controls/TopLevel.cs

@@ -15,7 +15,6 @@ using Avalonia.LogicalTree;
 using Avalonia.Media;
 using Avalonia.Platform;
 using Avalonia.Platform.Storage;
-using Avalonia.Reactive;
 using Avalonia.Rendering;
 using Avalonia.Styling;
 using Avalonia.Utilities;

tests/Avalonia.RenderTests/Controls/CustomRenderTests.cs

@@ -88,7 +88,7 @@ namespace Avalonia.Direct2D1.RenderTests.Controls
                 Height = 200,
                 Child = new CustomRenderer((control, context) =>
                 {
-                    using (var transform = context.PushPreTransform(Matrix.CreateTranslation(100, 100)))
+                    using (var transform = context.PushTransform(Matrix.CreateTranslation(100, 100)))
                     using (var clip = context.PushClip(new Rect(0, 0, 100, 100)))
                     {
                         context.FillRectangle(Brushes.Blue, new Rect(0, 0, 200, 200));
@@ -112,7 +112,7 @@ namespace Avalonia.Direct2D1.RenderTests.Controls
                 Height = 200,
                 Child = new CustomRenderer((control, context) =>
                 {
-                    using (var transform = context.PushPreTransform(Matrix.CreateTranslation(100, 100)))
+                    using (var transform = context.PushTransform(Matrix.CreateTranslation(100, 100)))
                     using (var clip = context.PushClip(new Rect(0, 0, 100, 100)))
                     {
                         context.FillRectangle(Brushes.Blue, new Rect(0, 0, 200, 200));

tests/Avalonia.RenderTests/Media/ConicGradientBrushTests.cs

@@ -200,7 +200,7 @@ namespace Avalonia.Direct2D1.RenderTests.Media
                 Child = new DrawnControl(c =>
                 {
                     c.DrawRectangle(brush, null, new Rect(0, 0, 100, 100));
-                    using (c.PushPreTransform(Matrix.CreateTranslation(100, 100)))
+                    using (c.PushTransform(Matrix.CreateTranslation(100, 100)))
                         c.DrawRectangle(brush, null, new Rect(0, 0, 100, 100));
                 }),
             };

tests/Avalonia.RenderTests/Media/LinearGradientBrushTests.cs

@@ -95,7 +95,7 @@ namespace Avalonia.Direct2D1.RenderTests.Media
                 {
                     c.DrawRectangle(brush, null, new Rect(0, 0, 100, 100));
 
-                    using (c.PushPreTransform(Matrix.CreateTranslation(100, 100)))
+                    using (c.PushTransform(Matrix.CreateTranslation(100, 100)))
                         c.DrawRectangle(brush, null, new Rect(0, 0, 100, 100));
                 }),
             };

tests/Avalonia.RenderTests/Media/RadialGradientBrushTests.cs

@@ -185,7 +185,7 @@ namespace Avalonia.Direct2D1.RenderTests.Media
                 Child = new DrawnControl(c =>
                 {
                     c.DrawRectangle(brush, null, new Rect(0, 0, 100, 100));
-                    using (c.PushPreTransform(Matrix.CreateTranslation(100, 100)))
+                    using (c.PushTransform(Matrix.CreateTranslation(100, 100)))
                         c.DrawRectangle(brush, null, new Rect(0, 0, 100, 100));
                 }),
             };

tests/Avalonia.RenderTests/Media/TextFormatting/TextLayoutTests.cs

@@ -312,7 +312,7 @@ namespace Avalonia.Direct2D1.RenderTests.Media
                     var rotate = Matrix.CreateTranslation(-100, -100) *
                         Matrix.CreateRotation(MathUtilities.Deg2Rad(90)) *
                         Matrix.CreateTranslation(100, 100);
-                    using var transform = c.PushPreTransform(rotate);
+                    using var transform = c.PushTransform(rotate);
                     c.DrawRectangle(Brushes.Yellow, null, rect);
                     t.Draw(c, rect.Position);
                 }),

tests/Avalonia.Skia.UnitTests/Media/TextFormatting/TextFormatterTests.cs

@@ -792,7 +792,7 @@ namespace Avalonia.Skia.UnitTests.Media.TextFormatting
             public override double Baseline => 0;
             public override void Draw(DrawingContext drawingContext, Point origin)
             {
-                using (drawingContext.PushPreTransform(Matrix.CreateTranslation(new Vector(origin.X, 0))))
+                using (drawingContext.PushTransform(Matrix.CreateTranslation(new Vector(origin.X, 0))))
                 {
                     drawingContext.FillRectangle(_fill, _rect);
                 }