Check automatic variable availability

In comparing the Preference Variables documentation for PowerShell 6.x and newer:
https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_preference_variables?view=powershell-6

to the Preference Variables documentation for PowerShell 5.1:
https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_preference_variables?view=powershell-5.1

it seems that a number of Preference Variables were removed/deprecated from PowerShell. I just ran into this problem unexpectedly on a script when testing it on PowerShell 6.x.

To help with this problem, I would like the PSUseCompatibleCommands feature of PSScriptAnalyzer to flag the usage of deprecated Preference Variables and state that they are not compatible with PowerShell 6.0 and newer (on any platform including Windows).

Comienza comparando la documentación vinculada de about_Preference_Variables de PowerShell 6.x y 5.1, y después localiza la característica PSUseCompatibleCommands en PSScriptAnalyzer. Se considera hecho cuando el uso de variables de preferencia obsoletas se marca con una indicación de que es incompatible con PowerShell 6.0 y versiones posteriores en todas las plataformas.