add NotifyIcon and Notification docs

src/Shared/HandyControlDemo_Shared/UserControl/Main/AppNotification.xaml

@@ -1,12 +1,12 @@
 <Border x:Class="HandyControlDemo.UserControl.AppNotification"
-             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
-             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-             xmlns:hc="https://handyorg.github.io/handycontrol"
-             Background="White"
-             BorderThickness="1"
-             BorderBrush="{DynamicResource BorderBrush}"
-             Width="320"
-             Height="518">
+        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:hc="https://handyorg.github.io/handycontrol"
+        Background="White"
+        BorderThickness="1"
+        BorderBrush="{DynamicResource BorderBrush}"
+        Width="320"
+        Height="518">
     <hc:SimplePanel>
         <Path Margin="0,36,0,0" VerticalAlignment="Top" Width="70" Height="70" Data="{StaticResource LogoGeometry}" Fill="#f06632"/>
         <TextBlock Text="HandyControl" FontSize="30" Foreground="{StaticResource PrimaryBrush}" HorizontalAlignment="Center" Margin="0,122,0,0" VerticalAlignment="Top"/>