Context menu item to pin window to all desktops

https://superuser.com/questions/950960/pin-applications-to-multiple-desktops-in-windows-10

```C
exstyle = GetWindowLongPtr(hwndPtr, GWL_EXSTYLE);
exstyle |= WS_EX_TOOLWINDOW
SetWindowLongPtr(hwndPtr, GWL_EXSTYLE, exstyle);
```

https://www.meziantou.net/extending-the-system-menu-to-add-advanced-commands-in-dotnet.htm