Add scripts to mark shipped API

Derived from:

- https://github.com/dotnet/roslyn/blob/494a8afcbf6df00df329de9f6a51c54514b1665f/scripts/PublicApi/mark-shipped.ps1
- https://github.com/dotnet/roslyn/blob/494a8afcbf6df00df329de9f6a51c54514b1665f/scripts/PublicApi/mark-shipped.cmd

Author: atifaziz

.config/dotnet-tools.json

@@ -19,6 +19,12 @@
       "commands": [
         "meziantou.validate-nuget-package"
       ]
+    },
+    "powershell": {
+      "version": "7.4.0",
+      "commands": [
+        "pwsh"
+      ]
     }
   }
 }

tools/mark-shipped.cmd

@@ -0,0 +1,2 @@
+@echo off
+dotnet pwsh -NoProfile -ExecutionPolicy RemoteSigned -File "%~dpn0.ps1"

tools/mark-shipped.ps1

@@ -0,0 +1,44 @@
+[CmdletBinding(PositionalBinding=$false)]
+param ()
+
+Set-StrictMode -Version 2.0
+$ErrorActionPreference = 'Stop'
+
+function MarkShipped([string]$dir)
+{
+    $shippedFilePath = Join-Path $dir 'PublicAPI.Shipped.txt'
+    [array]$shipped = Get-Content $shippedFilePath
+
+    $unshippedFilePath = Join-Path $dir 'PublicAPI.Unshipped.txt'
+    [array]$unshipped = Get-Content $unshippedFilePath | ? { $_ -and $_ -notmatch '^#' }
+
+    $removed = @()
+    $removedPrefix = '*REMOVED*';
+    Write-Verbose "Processing $dir"
+
+    foreach ($item in $unshipped)
+    {
+        if ($item.StartsWith($removedPrefix))
+        {
+            $item = $item.Substring($removedPrefix.Length)
+            $removed += $item
+        }
+        else
+        {
+            $shipped += $item
+        }
+    }
+
+    $shipped |
+        Sort-Object |
+        ? { -not $removed.Contains($_) } |
+        Out-File $shippedFilePath -Encoding Ascii
+
+    '#nullable enable' | Out-File $unshippedFilePath -Encoding Ascii
+}
+
+foreach ($file in Get-ChildItem -re -in 'PublicApi.Shipped.txt')
+{
+    $dir = Split-Path -parent $file
+    MarkShipped $dir
+}