Example code is outdated and doesn't work

The example code appears to come from the previous Microsoft.Windows.Shell.dll implementation. Eg it is wrong to do

<Setter Property="shell:WindowChrome.WindowChrome">

it should be

<Setter Property="WindowChrome.WindowChrome">

because WindowChrome is in the PresentationFramework assembly now.

Also {x:Static shell:SystemParameters2.Current} doesn't work because apparently that property was dropped completely when this code was moved into the PresentationFramework.

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* ID: 51b688a4-ceb5-6e73-78c1-45e7a4c37ab8
* Version Independent ID: 56918f97-3d7a-eac5-7141-3064ca392b98
* Content: [WindowChrome Class (System.Windows.Shell)](https://docs.microsoft.com/en-us/dotnet/api/system.windows.shell.windowchrome?redirectedfrom=MSDN&view=netframework-4.7.2)
* Content Source: [xml/System.Windows.Shell/WindowChrome.xml](https://github.com/dotnet/dotnet-api-docs/blob/master/xml/System.Windows.Shell/WindowChrome.xml)
* Product: **dotnet-api**
* GitHub Login: @dotnet-bot
* Microsoft Alias: **dotnetcontent**