Merge pull request #3495 from sharkdp/powershell_completions

Update PowerShell completions for compatibility with PowerShell v5.1

CHANGELOG.md

@@ -12,7 +12,7 @@
 
 ## Other
 - Improve README documentation on pager options passed to less, see #3443 (@injust)
-
+- Make PowerShell completions compatible with PowerShell v5.1, see #3495 (@keith-hall)
 - Use more robust approach to escaping in Bash completions, see #3448 (@akinomyoga)
 
 ## Syntaxes

assets/completions/_bat.ps1.in

@@ -49,7 +49,10 @@ Register-ArgumentCompleter -Native -CommandName '{{PROJECT_EXECUTABLE}}' -Script
         }
         '*;--language' {
             Get-MyLanguages |
-            ForEach-Object {[CompletionResult]::new(($_.MyParameter -replace "^(.*)$", '''$1'''), $_.MyParameter, [CompletionResultType]::ParameterName, $_.MyDescription ?? '_no value_')}
+            ForEach-Object {
+                $desc = if ($null -eq $_.MyDescription) { '_no value_' } else { $_.MyDescription }
+                [CompletionResult]::new(($_.MyParameter -replace "^(.*)$", '''$1'''), $_.MyParameter, [CompletionResultType]::ParameterName, $desc)
+            }
             break
         }
         '*;--theme' {