Improve Button and ToggleButton styling

src/Avalonia.Themes.Default/Button.xaml

@@ -22,13 +22,13 @@
       </ControlTemplate>
     </Setter>
   </Style>
-  <Style Selector="Button:pointerover /template/ ContentPresenter">
+  <Style Selector="Button:pointerover">
     <Setter Property="BorderBrush" Value="{DynamicResource ThemeBorderMidBrush}"/>
   </Style>
-  <Style Selector="Button:pressed  /template/ ContentPresenter">
+  <Style Selector="Button:pressed">
     <Setter Property="Background" Value="{DynamicResource ThemeControlHighBrush}"/>
   </Style>
   <Style Selector="Button:disabled">
     <Setter Property="Opacity" Value="{DynamicResource ThemeDisabledOpacity}"/>
   </Style>
-</Styles>
+</Styles>

src/Avalonia.Themes.Default/ToggleButton.xaml

@@ -22,17 +22,17 @@
       </ControlTemplate>
     </Setter>
   </Style>
-  <Style Selector="ToggleButton:checked /template/ ContentPresenter">
+  <Style Selector="ToggleButton:checked">
     <Setter Property="Background" Value="{DynamicResource ThemeControlHighBrush}"/>
     <Setter Property="BorderBrush" Value="{DynamicResource ThemeBorderMidBrush}"/>
   </Style>
-  <Style Selector="ToggleButton:pointerover /template/ ContentPresenter">
+  <Style Selector="ToggleButton:pointerover">
     <Setter Property="BorderBrush" Value="{DynamicResource ThemeBorderMidBrush}"/>
   </Style>
-  <Style Selector="ToggleButton:pressed  /template/ ContentPresenter">
+  <Style Selector="ToggleButton:pressed">
     <Setter Property="Background" Value="{DynamicResource ThemeControlHighBrush}"/>
   </Style>
   <Style Selector="ToggleButton:disabled">
     <Setter Property="Opacity" Value="{DynamicResource ThemeDisabledOpacity}"/>
   </Style>
-</Styles>
+</Styles>