Include $PSItem in auto variables in addition to $_

While it would be nice to only present `$PSItem` to encourage people to
use it, that may confuse people who still use `$_` and don't know that
they are the same.

Co-authored-by: Patrick Meinecke <SeeminglyScience@users.noreply.github.com>

Author: 2 people

src/PowerShellEditorServices/Services/DebugAdapter/DebugService.cs

@@ -756,7 +756,7 @@ private bool AddToAutoVariables(PSObject psvariable, string scope)
             // Some local variables, if they exist, should be displayed by default
             if (psvariable.TypeNames[0].EndsWith("LocalVariable"))
             {
-                if (variableName.Equals("_"))
+                if (variableName.Equals("PSItem") || variableName.Equals("_"))
                 {
                     return true;
                 }