chore: add show label property for toggle button.

src/Shared/HandyControl_Shared/Controls/Attach/ToggleButtonAttach.cs

@@ -0,0 +1,14 @@
+using HandyControl.Data;
+using System.Windows;
+
+namespace HandyControl.Controls;
+
+public class ToggleButtonAttach
+{
+    public static readonly DependencyProperty ShowLabelProperty = DependencyProperty.RegisterAttached(
+        "ShowLabel", typeof(bool), typeof(ToggleButtonAttach), new FrameworkPropertyMetadata(ValueBoxes.FalseBox, FrameworkPropertyMetadataOptions.Inherits));
+
+    public static void SetShowLabel(DependencyObject element, bool value) => element.SetValue(ShowLabelProperty, ValueBoxes.BooleanBox(value));
+
+    public static bool GetShowLabel(DependencyObject element) => (bool) element.GetValue(ShowLabelProperty);
+}