You should be able to download the Segoe MDL2 Assets
font family from here or just copy the .ttf file over from a Windows 10 instance: https://www.azfonts.net/families/segoe-mdl2-assets.html
Once you have done this, you should add the .ttf file to your project as a resource. You can then use the symbols like this:
<!-- Minimize -->
<TextBlock Text="Value="" FontFamily="pack://application:,,,/#Segoe MDL2 Assets" FontSize="10" />
<!-- Maximize -->
<TextBlock Text="Value="" FontFamily="pack://application:,,,/#Segoe MDL2 Assets" FontSize="10" />
<!-- Restore -->
<TextBlock Text="Value="" FontFamily="pack://application:,,,/#Segoe MDL2 Assets" FontSize="10" />
<!-- Close -->
<TextBlock Text="Value="" FontFamily="pack://application:,,,/#Segoe MDL2 Assets" FontSize="10" />
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