AI: Sure, I can help you modify the script. Please try the following script:
$currentDir = Get-Location
Set-Location -Path $folder
$files = Get-ChildItem -Recurse
$fileTypes = $files | Select-Object Extension -Unique
$fileTypes | Out-File -FilePath Result.txt
Set-Location -Path $currentDir

This script should take all of the files from the specified folder and write their file extensions to a text file in the current working directory. Don't forget to substitute "folder" with the path to the desired folder.