Add a new keyword clean that has been added in PowerShell 7.3.

src/EditLexers/stlPowerShell.c

@@ -3,7 +3,7 @@
 
 static KEYWORDLIST Keywords_PS1 = {{
 //++Autogenerated -- start of section automatically generated
-"assembly base begin break catch class command configuration continue data define do dynamicParam dynamicparam "
+"assembly base begin break catch class clean command configuration continue data define do dynamicParam dynamicparam "
 "else elseif end enum exit filter finally for foreach from function hidden if in inlineScript inlinescript interface "
 "module namespace parallel param private process public return sequence static switch throw trap try type until using "
 "var while workflow "

tools/lang/PowerShell.ps1

@@ -8,7 +8,7 @@
 # https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_language_keywords
 # https://docs.microsoft.com/en-us/powershell/scripting/lang-spec/chapter-02#231-keywords
 begin break
-catch class continue
+catch class clean continue
 data define do dynamicparam dynamicParam
 else elseif end enum exit
 filter finally for foreach from function