Check for Microsoft's WSL in open_command (#6751)
This will work only on files and directories in a DrvFs mount, i.e.
that can be translated to a Windows drive path.
For example: /mnt/c/Users/user.
Files and folders inside the LXSS directory can't be handled in
Windows, they must be ONLY used by the WSL subsystem. That's why
you won't be able to open your $HOME directory, for instance.
See https://blogs.msdn.microsoft.com/commandline/2016/11/17/do-not-change-linux-files-using-windows-apps-and-tools/