Remove the extra new line form List formatting (PowerShell#18185)

Author: daxian-dbw

src/System.Management.Automation/FormatAndOutput/common/BaseOutputtingCommand.cs

@@ -456,9 +456,16 @@ private void ProcessFormatStart(FormatMessagesContextManager.OutputContext c)
         /// <param name="c">Current context, with Fs in it.</param>
         private void ProcessFormatEnd(FormatEndData fe, FormatMessagesContextManager.OutputContext c)
         {
-            // Console.WriteLine("ProcessFormatEnd");
-            // we just add an empty line to the display
-            this.LineOutput.WriteLine(string.Empty);
+            if (c is FormatOutputContext foContext
+                && foContext.Data.shapeInfo is ListViewHeaderInfo)
+            {
+                // Skip writing out a new line for List view, because we already wrote out
+                // an extra new line after displaying the last list entry.
+                return;
+            }
+
+            // We just add an empty line to the display.
+            LineOutput.WriteLine(string.Empty);
         }
 
         /// <summary>

test/powershell/Modules/Microsoft.PowerShell.Utility/Format-List.Tests.ps1

@@ -37,7 +37,7 @@ Describe "Format-List" -Tags "CI" {
     }
 
     It "Should produce the expected output" {
-        $expected = "${nl}testName : testValue${nl}${nl}${nl}"
+        $expected = "${nl}testName : testValue${nl}${nl}"
         $in = New-Object PSObject
         Add-Member -InputObject $in -MemberType NoteProperty -Name testName -Value testValue
 
@@ -201,7 +201,6 @@ dbda : KM
 消息 : 千
 
 
-
 "@
         $expected = $expected -replace "`r`n", "`n"
 
@@ -224,7 +223,6 @@ float   : 9876.543
 decimal : 4567.123456789
 
 
-
 "@
 
         $actual = $o | Format-List | Out-String