Using TabExpansionPlusPlus to tab-complete CName -> HostName

ComputerName.Completer.ps1

Register-ArgumentCompleter -ParameterName ComputerName -ScriptBlock {
param(            
    $commandName,             
    $parameterName,             
    $wordToComplete,             
    $commandAst,             
    $fakeBoundParameter            
)    
    $record = [System.Net.Dns]::Resolve($wordToComplete)
    if ($record) {
        $name = $record.HostName -replace '\..*$'
        [System.Management.Automation.CompletionResult]::new(
            $name,
            $name,
            [System.Management.Automation.CompletionResultType]::ParameterValue,
            "Computer $name with aliases $($record.Aliases -join ', ')"
        )
    }
}