Rename 'Get-Subsystem' to 'Get-PSSubsystem' and fix two minor issues (#13765)

src/System.Management.Automation/FormatAndOutput/DefaultFormatters/PowerShellCore_format_ps1xml.cs

@@ -738,7 +738,7 @@ namespace System.Management.Automation.Runspaces
                 "System.Management.Automation.Subsystem.SubsystemInfo",
                 TableControl.Create()
                     .AddHeader(Alignment.Left, width: 17, label: "Kind")
-                    .AddHeader(Alignment.Left, width: 15, label: "SubsystemType")
+                    .AddHeader(Alignment.Left, width: 18, label: "SubsystemType")
                     .AddHeader(Alignment.Right, width: 12, label: "IsRegistered")
                     .AddHeader(Alignment.Left, label: "Implementations")
                     .StartRowDefinition()

src/System.Management.Automation/engine/InitialSessionState.cs

@@ -5395,7 +5395,7 @@ end {
 
             if (ExperimentalFeature.IsEnabled("PSSubsystemPluginModel"))
             {
-                cmdlets.Add("Get-Subsystem", new SessionStateCmdletEntry("Get-Subsystem", typeof(Subsystem.GetSubsystemCommand), helpFile));
+                cmdlets.Add("Get-PSSubsystem", new SessionStateCmdletEntry("Get-PSSubsystem", typeof(Subsystem.GetPSSubsystemCommand), helpFile));
             }
 
             foreach (var val in cmdlets.Values)

src/System.Management.Automation/engine/Subsystem/Commands/GetPSSubsystemCommand.cs

@@ -6,12 +6,12 @@
 namespace System.Management.Automation.Subsystem
 {
     /// <summary>
-    /// Implementation of 'Get-Subsystem' cmdlet.
+    /// Implementation of 'Get-PSSubsystem' cmdlet.
     /// </summary>
     [Experimental("PSSubsystemPluginModel", ExperimentAction.Show)]
-    [Cmdlet(VerbsCommon.Get, "Subsystem", DefaultParameterSetName = AllSet)]
+    [Cmdlet(VerbsCommon.Get, "PSSubsystem", DefaultParameterSetName = AllSet)]
     [OutputType(typeof(SubsystemInfo))]
-    public sealed class GetSubsystemCommand : PSCmdlet
+    public sealed class GetPSSubsystemCommand : PSCmdlet
     {
         private const string AllSet = "GetAllSet";
         private const string TypeSet = "GetByTypeSet";
@@ -37,7 +37,7 @@ namespace System.Management.Automation.Subsystem
             switch (ParameterSetName)
             {
                 case AllSet:
-                    WriteObject(SubsystemManager.GetAllSubsystemInfo());
+                    WriteObject(SubsystemManager.GetAllSubsystemInfo(), enumerateCollection: true);
                     break;
                 case KindSet:
                     WriteObject(SubsystemManager.GetSubsystemInfo(Kind));

test/powershell/engine/Help/HelpSystem.Tests.ps1

@@ -16,7 +16,7 @@ $script:cmdletsToSkip = @(
     "Get-ExperimentalFeature",
     "Enable-ExperimentalFeature",
     "Disable-ExperimentalFeature",
-    "Get-Subsystem"
+    "Get-PSSubsystem"
 )
 
 function UpdateHelpFromLocalContentPath {